Pain = no loss?

I have no idea if you wonderful experts know anything about this, but here it is.:

I have found that when my body is in "severe pain" mode (am waiting for back surgery in December and am often bed-bound by acute pain) I do not release weight.  Is this just because I am moving around less (although I have released 60 pounds in 4+ months, with VERY little exercize)...or does the pain somehow interfere with whatever I need to lose weight?  I have heard that stress can interfere with weight loss, and this is DEFINATELY high stress!

(I have been at one weight for about a month, and my eating patterns remain about the same.)

Thanks!  Linda