Been a few months since I posted - update. I've continued to smoke regularly (so by my math this would be smoking for the last 7-8 months after stopping for a year and a half). My problem has not gotten worse - in fact it has improved. Why? I really don't know. I also had an appointment with a new doctor - who diagnosed my issue as Tietze syndrome (which has a lot in common to Costochondritis) after my description of symptoms. Lab and blood work did not reveal any concerns. Not really a treatable condition - and not fully understood. I still get the feeling this issue is more complicated than a couple of labels, and there may be a lot of different reasons people get this pain. To answer a question - there was nothing of note on my x-ray scans, or at least nothing my previous doctor could see. I think there is real truth to -a senile fungus- posts. When I smoke, I've always had the tendency to over indulge, because I like to get where I want to be fast - and move on to other stuff. I've thought about this pain a lot - and I notice that when you take a particularly big hit - the area behind your ribs can get absurdly tight. You don't think about it, because your brain is still reeling from oxygen deprivation and the THC onset effect. People who smoke and get this pain (generally speaking) seem to immediately jump to the conclusion this is a result of the smoke, but perhaps this can be a completely mechanical issue - correctable with proper physical rehab. I generally am very physically active, and have noticed no difference in how I feel after I work out (better or worse), but I have not specifically done exercises for this area of my body. I could do a lot to improve posture, strengthen my core and upper body. Regardless, in my case I had a year of hell - another year of discomfort, and now I'm back to regular smoking. While I can still feel the point of discomfort, and it does vary in how it feels - the condition has improved dramatically (I always hesitate to openly state this - its like taunting the issue always makes it feel worse the next day...).