“Constant cough and pain?”

I got bronchitis on March 19 and later on, was told I have chronic bronchitis and mostly asthma. Ever since March, I have been coughing nonstop, and having mucus. It’s been 4 months and I still have the cough but on Sunday, June 19 I started to feel a sharp stabbing pain in my chest right side, under my breast and on my side, and on my upper right back. It hurts when I breathe in, cough, and move around. I went to my family doctor on Monday June 20 and she sent us to get an X-ray and blood work. The next day on Tuesday, June 21 I got a call from the family doctor that said my X-ray came out clear but my blood work showed that I might have a blood clot so she said to go to the hospital right away. That’s what we did exactly. The doctors in the hospital performed more blood work, ultrasound, and an ect and it all came out clean. They said they don’t know what is wrong but they think it could be costochondritis due to coughing a lot. I don’t know if it’s that, and I’m worried that it might be something more serious like lung cancer. I also feel like I’m choking on my own mucus and cough sometimes. The cough is constant.