I'm a 21 year old male, who started smoking almost two years back. Started smoking marijuana too, about a year and nine months ago. I smoke on an average 2 joints a day. There were a few days I din't smoke, but then there were a lot of days I smoked a lot(5-7 joints). I've cut down on cigarettes a lot. From about 5-10 a day to 1 or 2 and currently none. But the joints I smoke are mostly marijuana with less than half a cigarette's tobacco. Also, I used to workout consistently(6 months) before this period and another 6 months on and off in between this period. 

   Coming to the problem, I went back to the gym about 3 weeks back. Worked out for a week. Couldn't go for a couple of days and then worked out for the rest of the week. And this week, I've been having lower chest pain whenever I jump. The lower part of my lungs, both sides, feel heavy. No problems otherwise, no sleeping problems or breathing problems. When I take a very deep breath, I can feel the pain slightly. I also have back pain, right behind this area when I'm jumping or doing crunches. I din't work out for the last 3 days, but today I did. Except when jumping, the pain was never that noticeable. 

I'm getting a bit worried. I've brought down all my smoking to about 1 joint a day. What could this be? Has anybody had any similar experiences? Should I continue working out? Also to be noted, out of the days I din't go to the gym, I smoked a lot on a few of those days(a week and a half ago). Bong shots. Dhoka in Medwakh pipe. And the usual joints and cigarettes.

Please do share your experience and knowledge.