IBS theory, cause and effect?

I have a very good PCP who is very smart and has helped me with IBS which he diagnosed about 7 months ago. I would have terrible pain in the transverse colon area (about the diaphram area). I did not feel constipated, it felt more like my digestion would just stop and i would not have a BM for 2 days after which they were normal. Now it has changed to loose stools and bloating. I am a 39 year old male in generally good health. I did notice that dairy products would set off the IBS, so i have discontinued milk and cheese. I used to drink at least 1/2 gal of milk a day, i am now wondering if the lack of calcium and vitamin D had changed my symptoms of IBS? I also wonder if adding a simple multi-vitamin would help?

I have also suffered a herniated disk at L2 and wonder if the scarring associated with the ruptured disk has caused adheasions to the intestinal tract which may be causing the night-time back pain and IBS..... Am i off track here or is this a possible reason? Even though i do have bad days, the subject interests me and wonder if my theory has merit.