Can anyone help me with my problem?

Hi, I have been having chest pain for around 4 months (since I quit smoking) It hurts when I take a deep breath in and exhale deep. It also hurts when im not breathing heavy. I visited my GP who said it was the muscles in my chest from stopping smoking. It didn't disappear and ibuprofen wasn't easing the pain. Last week the pain started to get worse so I went to A&E. There I had a ECG and it was all fine. My pulse and BP were also normal. While I was there they gave me 1 ibuprofen and 2 co-codamol to try and ease the pain which also didn't work. I spoke to a Dr who thought it could be 1 of 2 things Acid or Pleurisy. They are both different treatments. They sent me away with Lansoprazole 30mg for gastric and acid 3 days later and im still experiencing the pain. Could anyone help me with my diagnosis? The pain really hurts and no pain killers I have relieve it