According to what some of the doctors at the Cleveland Clinic tell their patients, those with a j-pouch should restrict lifting to 25 pounds. Apparently, it can lead to pouch prolapse or rupture. But, I was never told this by any of my doctors.
A decade after my surgery I developed chronic low back pain, which was primarily in the upper buttock region. No injuries or related pouchitis. I also had bouts of tendonitis that seemed out of the blue. Eventually, I was referred to a rheumatologist, who diagnosed enteropathic arthritis. This is a form of spondylitis. I was put on biologics (first Humira, now Simponi) and I have been much better since then.
This form of arthritis has a course independent of the IBD course.
Some people do seem to develop chronic pain from the scar tissue between the pouch and the posterior abdominal wall, so you cannot assume it is the enteropathic arthritis. Just be aware of it as a possibility. Also, pouchitis could lead to the form of arthritis that is more closely associated with IBD activity. Bleeding is not usually associated with pouchitis, so do not assume that it is a primary symptom. Increased frequency is the primary symptom, usually with feelings of malaise or fatigue.
You may want to find out if this is pouchitis, then seek a rheumatology referral if the pain persists.
Jan