I can share my experience with you but do not know definately what your problem is. I experience bloating, pain, and constipation and doctors prescribed me for IBS. It turns out I do have IBS (stress induced) but I control it with my eating habits. Raw fruits and vegetables give me bloating and because of constipation I am also unable to release gasses (faurts) like other people. It is alway better if I cook vegetables, fruit in small portions, and coffee, alchohol, peanuts, beef, pork, and many more are big trigger foods for me. I read many websites and found out the general trigger foods and safer foods for digestion. I also had leaky gut syndrome which is now repaired which made things worse at the time.
For me it turned out IBS was not the cause of everything but I actually had several health problems that were not related. Your pain in back and neck could possibly be something different altogether so maybe..maybe you have two different problems.
You can also check if you have candida because for some people that contributes to many of those symtoms.
If you can, see your doctor, research more, and try different foods to help find out the causes of your problem.
Have you ever been tested for celiacs? They do a biopsy for that. Many people who have celiac have skin rashes with red spots or blisters and it can cause other problems like muscle and joint pain and loose stools/abdominal cramps.
I had the same problem for nine years, from 14-23. It got progressively worse to the point that I developed food allergies and lost nearly all my muscle tone. I also suffered from anxiety and depression during that time, which I believed was due to being sick and yet not having any doctor believe me. I only had allergy indicators in blood tests and one slightly abnormal thyroid test out of many. After nearly giving up on ever feeling normal again my mom told me about a diet her friend had tried and had great results for nearly the same symptoms as me (she also had developed vision problems). It was a candida diet recommended to her by a chiropractor. I did some research and a systemic candida infection describe exactly what I went through and also explained why doctors had failed to diagnose me and why I had been getting so much sicker, despite taking anti-biotics and steroids. Candida cells exist naturally in your digestive system along with healthy probiotic organisms. Normally the presence of probiotics keep candida in check, but when taking antibiotics probiotics are killed and candida can quickly reproduce. Candida damages the digestive tract causing all of those horrible stomach issues and then eventually breaks the blood barrier in a damaged area and becomes a systemic infection causing fatigue, muscle pain, depression, and so many other problems. Tests are a blood or fecal test, but they aren't the most reliable tests as candida is naturally present in some amount in every body and some people don't have an overgrowth but a sensitivity issue. Treatment can be approached a number of ways but most people first detox (heavy metals especially) first since candida binds to heavy metal and recovering from the infection is easier with a clean body. Next there is a combination of replenishing nutrient deficiencies(find out with blood tests) and taking probiotics and anti-fungal prescription medication(or herbal remedies that work the same) and following a candida diet (anywhere from three weeks to four months depending on the severity of infection). The diet was really, really, really hard. It involves cutting out like all sugar (even most fruits!), alcohol, coffee, and several grains that are in pretty much everything. If you can get used to vegetables (raw and juice form mainly) you'll be fine after the first week or two. There is an effect during that first week and half of the diet called the die off (there's a medical term for it I'm blanking on) and that is difficult to deal with, my skin issues and stomach issues got worse and I was very irritable all the time (but in reading and talking to a nutritionist I had prepared myself for all of this). Anyway to wrap this long post up on a hopeful note, after following the strict diet for three months and sticking to some lifestyle changes, diet, exercise, quit smoking, etc. I'm happy to say I've found tremendous relief. I don't think I've completely beat it yet, my tests are within acceptable range again though. But my skin is so much softer and even colored and younger looking and my stomach almost never bothers me (only when I drink or eat something I know I shouldn't have). The best part is I have energy again to do things, it was like I was walking in a daze all of the time just waiting till I could lie down (I can actually sleep when I lie down now too, which I had forgotten how naturally it could happen). I would definitely recommend looking into it especially since it seems like a similar experience among people diagnosed that they go years suffering without any doctor being able to quite figure out the problem.
Also forgot to add major symptom I had developed progressively over years that has all but disappeared, rather miraculously, asthma.
I hope you've found relief by now as your posting was 8 (!) years ago! But I just wanted you, and anyone else out there suffering from IBS, to check out the FODMAP diet originally developed by a research team at Monash University in Melbourne, Australia in 2005.
I've suffered from IBS since I was 2 years old, so for over 50 years! A few months on this diet, and I haven't had an IBS episode in TWO years!! I don't need any other proof that they're onto something and this WORKS!