What Causes Heart Palpitations, Heaviness In Chest And Fatigue Post Treatment For Bronchitis?

I am a 34 year old female. For the past 2 months, I have had bronchitis. After 2 rounds of antibiotics and steroids, it seems to be getting better. About a month into the bronchitis, I started to have heart palpitations. I consulted my doctor, and he thought it was maybe a side effect of the antibiotic Azithromycin I was taking. A week after I saw my primary doctor about the palpitations, my heart rate increased and the palpitations grew every 10-30 seconds. I went to the ER. ER doctor me no diagnosis and just told me I had palpitations. She wrote me a prescription for Metoprolol. I took the medicine for a few days, but I was still concerned if this was my body developing a problem or a side effect of the antibiotic. I stopped Metoprolol. I have been fine for 2 weeks. No medications what so ever. Out of the blue, the palpitations came again. This time, I am experiencing a rubbing sensation all around the left side of my chest, horrible fatigue, headaches, dizziness, pain all up and down left side of my neck, left sided shoulder pain, nausea, insomnia and weakness. I have been looking online for heart related issues and I came across Pericardia. Does this sound like what I am experiencing and if so, what do I do?