abdominal pain!

Hi.
I have been having abdominal pain now for 5 months. It is actually in the lower right side, and it feels like pinching, specially if i bend over with my knees krossed. Also at night usually this part of my stomach swells up, like a baloon, and then the swelling goes down after a minute or less, but it comes back. This feels like it - whatever it is is going to come through my skin, and it is hard on the touch.
does anyone knows what this is? i've seen 6 doctors, done ct and ultra sound, but it all came back normal, doctors have no idea what it is. I fell good otherwise, no fever or anything like that, but this thing is really bothering me.
I would love to get any feedback, any advice.\
Thank you!
Sonja Tweet