What Causes Tightness And Burning Sensation In Chest And Dry Cough?

i have been sick for three weeks. Started out sinuses and chest. Went to clinic and was givin amoxicillin with potassium 875 mg twice a day. 5 days later back at clinic still feeling no better. Givin levoquin 500 mg once a day and steroid. 3 days of antibiotic left and I feel bad. Sinuses are better but chest is tight, burning. I get winded and can't sleep on my side because it feels like i am crushing my lungs. Dry painful cough that sometimes has a brownish green phlegm. Pneumonia possible?