Xeloda muscle problems

I've had Xeloda treatment both before and after rectal cancer surgery and am having problems with muscle stiffness in buttocks, groin & low back which is very painful & debilitating and otherwise feel well. It began in June & lasted 2 months, floating around from one side to another. I tried physical therapy, massage therapy, naproxin, vicodin, gabapentin, heat, cold, chiropractic - and nothing helped. Then in Sept. it vanished, but has now reaccurred in the left groin area & I'm having a painful time walking.
Has anyone else experienced this? The hand/foot syndrome is still there, but not too debilitaing, as is the cold sensitivity from the oxyplatin.
My oncologist says this isn't likely caused by the chemo, but I did read it occurred in 10% of patients.
First round of Xeloda was fall 2009, second round spring 2010. Two months each time.