I also frequently get myofascial knots in my rib cage and unfortunately have few answers for treatment or prevention. Physical therapy can be helpful in addressing the knots and I do PT myself on the ones I can reach. I do mild stretches - just enough to get the muscles to move across the bones through the facia and try to move gently, but that doesn't seem to prevent the knots and the pain. Also recently diagnosed with FM.

Per my sleep med doctor, I take 3mg of melatonin about a hour before bed time and then a 7.5 mg Rx of Remeron for sleep, 2 arthritis strength (650mg) acetaminophen ER and sometimes 220mg naproxen at bedtime. Melatonin helps get me to sleep, Remeron helps me get back to sleep when I wake up due to pain. The naproxen may be helpful during the daytime.

Due to complexity, I'm thinking seeing a specialist or several different specialists would be advisable. I started with orthopedics because that was the simplest place to start.

All the best to you and your situation.