i get that alot and i smoke too..im 22 years old and have aniexty for years to the point where if i push my left boob up its tender and sore.
i get ramdom pains around that area also with the dizzyness and feeling sick, stress and smoking can be the cause of unknown pains like that. it cant surely be cancer as ul have a lump and cancer doesnt realy cause pain as for what my neighbour has told me and shes a nurse in the AnE (ER)
department, ive also had a 24hr ECG monitor and ECG scans etc too and it all come back normal it maybe stress related. go see your doctor and just get it checked out if this helps ive been to my doctor around 27 times in the last 8 months because of how im feeling, i dont care what they think of me.. hyprocondriac i dont care aslong as im getting answers of a doctor and there checking me over and helping me il go everyday. dont be afraid to see a doctor thats why there there.
hope your ok chin up :)