What Causes Heaviness In The Chest And Shortness Of Breath After Taking Amoxicillin 500mg?

July 6 I had a sore throat, which I usually gargle with warm salt water and everything is better. Well i had two twelve hour overnight shifts and wasn t able to keep up with the gargling. I took a road trip from florida to michigan on the tenth. i had a non productive cough (even though there was significant rattling in my lungs) the whole trip. On saturday the 11th I started using mucinex and continued gargling. On Sunday the 12th I started taking an antibiotic that i had (amoxicillin 500mg 3x day for 10 days. I have missed a few doses but am almost done with it, and feel a heaviness in my chest and shortness of breath. should i just continue taking and time will heal it, or should i go in for chest xrays and possibly a steroid or breathing treatment? thank you.