Hello Kster,
Welcome to the Pain Management Community. I am sorry to hear about your painful undiagnosed pain and symptoms.
You question seems to be more of a medical one than of pain management. Please know that you are always welcome here - that said here's a link to our General Health Community. I encourage you to post your question there also - as you should receive more responses:
http://www.medhelp.org/forums/General-Health
Excruciating pain in lower back and abdomen, unusual bowel issues and headaches can indicate a multitude of medical conditions and be very difficult to diagnosis.
You've consulted a urologist and will be seeing an orthopedic specialist - if he finds nothing I would certainly consult a gastroenterologist.
Don't give up, there is a reason for why you feel the way you do. The "swelling" noted in your lower back is interesting. I assume Endometriosis has been ruled out.
It may take awhile to determine the cause of your symptoms but keep searching. A bright physicians, maybe someone that looks outside the box and can see the total picture is what you need.
I wish I had more answers for you. As said by fntn, we don't know your labs or the results of other tests you may have had performed.
Be assertive. You are your own best advocate. No one know how you feel but you. If you pain isn't well controlled, speak up, Other medications may work better to manage your pain. Gabapentin did nothing for me. Research indicates that often the dose has to be very high to be effective - so high that the side effects are worse than the original pain. I found Lyrica to be a better option - not everyone would agree as we all respond differently to specific medications.
Tramadol seems to be the 1st choice of drug in managing pain. Those of us with mean chronic pain often find Tramadol ineffective - though some ppl do very well on it. Again it depends on the type of pain, level of pain and how your system utilizes the drug.
I hope you'll keep us posted. I'll be very interested to learn more - as well as the outcome of your search. I wish you the very best.
Take Care,
~Tuck