Has anyone checked you for Costochondritis
But its basically kind of like arthritis in the bones in the chest and symptoms feel like heart burn, heartattack, but no shortness of breath. My mom developed it after a triple by pass surgery. Also have you tried a chiropractor? No cracking, just the new activator they use now. But am good one who dies xrays and full evaluation first. Please keep us posted. And for the heck of it, try moist heat, or dry heat, and icy hot or one of the otc rubs and see if you get any relief 😮‍💨.