I just developed this rib cage pain a few days after a 10% Valium cut. I thought I had cracked a rib. It hurts when I lay down.
I've gone over my journal. Mine is often positional too and also seems to have a cycle to it. Almost seems to correspond with food time passing in gut??
I'm just guessing and since benzo w/d affects G-I too, I think in my case - maybe you too - it is the added pressure in the gut cavity pushing up on the chest cavity.
Gee, could also be a combo w/d sxs associated with the increased muscle, soft tissue and bone pain.
Have you tried alternating ice and heat on the area? That helped me some. I wouldn't suggest taking any NSAIDs (ibuprofen, like Motrin or Advil or naprosyn) for relief. From what I have experienced and read they can make w/d sxs worse. Some time Tylenol helps me too. But I try the ice and moist heat first. Star Gazer