Upper left back pain when I breathe in

Patient: For the past two months I have had a pain in my upper left back when i breathe in. I went to my doctor and he thought i had a blood clot in my lung but after tests, it wasn’t. They said I had pleurisy but talking to other sufferers my pain is nowhere near as bad, its more uncomfortable. If i pull my shoulders back it doesnt hurt to breathe in. I’m so worried I have a tumour on my lung?