Scared about Ongoing lung issues , thoughts advice please.

Hi their, I'm 29 years old, October I had a chest infection and was given doxycycline within 2 weeks I wasnt 100% and was given doxycycline again. Chest x ray all clear. Around a month after this I was getting quite out of breath a week later I was told I have pleurisy I have almost constant upper back pain inbetween my shoulder blades (tender to touch)also a pain when breathing deeply under my right collarbone and I'm concerned it could be lung cancer. I have 2 very young children and I cant focus on absolutely anything other than how I feel right now, also to add I was a previous smoker of around 7 years I actually quit when I had the chest infections. I dont feel right in myself I'm waking through night in pain with my upper back, my right leg feels quite heavy, I'm constantly throat clearing Thick mucous. and I now have to have a repeat x ray next week I'm a little nervous about,Thankyou for taking your time and reading