38 yr-old w/ hemorrhoid per anoscopy. chronic low back and right hip pain, stand at work. consistently flat stool; could this be from muscle tension?

Yes and maybe: Certainly, standing for a long period of time, such as at work, can result from muscle strain and be a factor in chronic low back & hip pain. Stretching/strengthening exercises should help. But "flat stool" needs more investigation in my view; hemorrhoids by themselves should not be sufficient to cause. I would ask doctor for more testing, probably flex sig or colonosocpy, to evaluate. Good luck:)