What Causes A Feel Of Movement And Pain Below The Left Rib Cage?

Hi, I am not suffering too much but something is bugging me from long time after my last checkup with doctor in December 2013. I feel there is some part of my body; just below (inwards) my left ribcage, which sometimes moves and I can feel it touching my ribcage which causes very little pain. At first, I thought it might be due to spleen enlargement but it was not. In December 2013, I felt long strokes of movements at that region causing pain and consulted doctor. He gave me some medicine concluding that I might some strain at that region and may be because of my weight, eating habits, seating and sleeping habits might have caused such issue. After taking medicine, pain was less. Doctor advised me to have some 5-6 scan of body at and near abdominal region if pain does not stop within 2-3 days after medication but I did not went for scanning as it was very costly and I keep on taking medicine till 5 days later to know pain was completely gone. Now (21st Aug 14), I feel there is some movement at same region again causing little pain and I am afraid that someday again I may have to face the long strokes which is painful. Medicine which I took was Nexpro 20 (8 AM and 8 PM) and flexar MR (8AM - 1PM - 8PM). Hence, I just want suggestion like what are the disease which can have following symptoms: 1. Movement of some body part just below/at left rib cage 2. Any enlarge of body part? 3. Severe cases where such things happens 4. One of my guess is related to some Gastrointestinal. But I want answers from experts.