I have psoriatic arthritis and fibromyalgia, why does getting a massage make my pain feel worse instead of better?

First....: I suspect your psoriatic arthritis is dominant! people who hurt don't sleep, and because psa affects tendons and ligaments, it is the disease i diagnose in place of fibro the most. It depends on the type of massage, how vigorous it is, and whether the person massaging you is trained. So many variables to explain why!

See details: Because you are putting pressure on muscles and other soft tissue structures that are already very sore and painful. I personally have not seen massage help very often in my patients with fm.