Pain in lower left back area

Sleeve done 8/21/14, this past week I have had an uncomfortable pain in my lower left back (almost feels like a big knot).  Sitting seems to be the worst, laying down seems to be the best.  Tried rubbing it thinking its a pulled muscle but I have not lifted etc.  Anyone else experience this?

It could be a ton of things from kidney stones to a muscle, to gallbladder issues, etc.  I'd suggest getting checked out by a doctor. 

Same thing happened to me this week - left lower back.   I was feeling more active (221->195 surg. 7/25/14).   It can be real agony.   I've had a dr & physio in - might be nothing more than that you've been a bit more active.   Unless it's one of the more serious things, it's more likely a pulled muscle/tweaked disk.   Key is:  rest for 48-72 hours, but no more.   Then start moving to extent you can take it.   Take Advil and or Tylenol, to ease the pain, but keep moving as much as you can, else you'll stiffen up.   Still hurts like a mofo, but a week ago (when it happened) I had to call 911.   

Hope it's nothing serious - it usually isn't.   Main thing is:  try to keep to your normal routine, in spite of the pain:  don't let it get real painful, but the lack of motion will hurt you more than tolerating the pain.   Mostly, these things tend to go away after 2-6 weeks apparently.  Good luck!