Pain in Left Middle Back/Flank???

I'm 7 months post op & all of sudden this morning I developed a pretty intense pain on the left side of my middle back/flank area.  Everytime I move it really hurts.  I saw my surgeon last week for a post-op check & everything was fine at that time.  Not sure if this is surgically related or not.  It doesn't feel like a pulled muscle a deeper pain.  I'm a little concerned.  Anyone have any ideas?

 Ok, strange, cause I am also 7 months out (5/2/11) and I just saw my surgeon and it was all fine but I have this pain in my left side, but it is not all the time.  It happens when I sit a certain way, or walk too much, or stand in one place to much.  It happens alot when I drive!  It is not so much pain as just like uncomfortable.  It is weird and it only happens in the middle of my back on the left side!  

I just thought it was from loss of muscle.  Now I 'm concerned.

I saw my dr. yesterday it was my 2 wk post op i told him i was having discomfort in my upper stomach and in pain in the middle of my back ..he asked if i still had my gallbladder and i said yes ...now they want to run test UPPER GI AND XRAYS... IT COULD BE GALLBLADDER..

I actually had by gallbladder removed at the same time I had my RNY surgery.

Could be a UTI. Left flank pain is very common with UTI's. Sometimes, it could be the only symptom. Might want to see your PCP and have it checked out.