Sensitive/dull pain sensation in left lung

[Ashwin_Ramesh]

Hi, I have been a cannabis smoker for about 8 months and have quit for the past 2 months because of this sensitive pain which comes and goes. It isn't sharp to cause intense pain but it causes discomfort. Last month I had an chest x-ray and ECG done, they had no issues, however I lost some inhaling capacity on PFT. The doctor said the pain is probably muscular but she wasn't sure. The pain has reduced since I quit but hasn't not gone completely. Does anyone have any idea of what this is, I'm getting very nervous about this and it's having a bad effect on my anxiety.