Lower Abdominal Pain

I am a 20 year old male with a relatively clean family history. About 2 months ago I started noticing a slight burning sensation in my lower left abdomen. I went to urgent care after three days when the feeling hadn't gone away. The doctor checked for a hernia and said I was fine. He then ordered an X-ray and a urine test. The urine test came back negative and the doctor said the X-ray looked fine. He said that it might just be mild constipation and told me to take a laxative. I did so the following day but it didn't really affect the burning feeling at all. After about 4 days, one night the pain got worse after eating. I was scared and asked my parents to take me to the hospital. So, we went to the ER. In the ER, the doctor ordered another urine test, a blood test and a CT scan. They all came back negative again. The doctor said that it could be ulcers and the pain was just manifesting itself in a different location. So, he gave me a 20 day prescription for Nexium. The Nexium made the burning sensation go away after a couple of days but I started getting other pains (in my lower back and chest). These other pains were mostly muscular pains that felt better when I used Icy hot. Since the discomfort was still there, I went to see a gastroentreologist and he checked me and ordered more blood tests and a fecal analysis. He also told me to stop taking Nexium because he seriously doubted that it was ulcers. The tests have just come back recently and they are also negative. The pain however is still there. It now effects not only my lower left side like it used to but also my lower right and sometimes my lower back. It comes and goes but it hasn't worsened since the beginning. Although there is no burning sensation anymore, it is still bothersome. I haven't lost any weight, I haven't lost my appetite. I generally feel okay except for the pain. My bowel movements are normal and so are my stools. I don't have any serious urges to go to the bathroom through out the day and there isn't any blood in my stools. No fever or vomiting. The only thing wrong is the pain.

Summary of my medical examinations:

Urgent Care (3 days after pain started):
Urine Analysis - Neg
X-Ray- Neg

ER(7 days after pain started):
Urine Analysis - Neg
CT Scan- Neg
Blood tests - Neg

Gastroentreologist(4 weeks after pain started):
Blood tests- Neg
Fecal Analysis- Neg


Is it still possible that I have something serious like Crohn's or Ulceritive Colitis? Would these have been found in the tests that have already been done? Or, should I go ahead and get a colonoscopy?

It's been almost 2 months since this whole thing started. If I had Crohn's or Ulceritive Colitis, would I be getting worse by this point?

Can it be Colon Cancer? Can this be found in the tests that have already been done?

The gastroentreologist doesn't seem too concerned and said that if I started feeling better, there is no reason to continue with more tests.

I'm sorry for the long post but I just wanted to state all the information. It is really frustrating to deal with this (especially when I don't know what it is).

I should also mention that the reason that I'm frantically looking for answers is that I will be studying abroad in England in about 2 months. If I do have Crohn's, UC, Cancer or something serious, I should probably stay close to home until I get a handle on things.

[d3nv3r]

I should also note that I have some bloating/gas from time to time. Especially when I am hungry. I also have some lower back pain also comes and goes. And, I am noticing undigested food in my stools for awhile.