Help me im 17 and affraid im dieing pleas read?

the day before christmas my heart was pounding i was very short of breath went to the hospital said i had uri the for 3 weeks i was hardly breathing then felt ok low appatite but still left side chest pain come and go still have it getting better ech day not by much and direa whats it sound like im afraid if i laugh allot or blow my nose my left side heart area hurts am i dieing also i have much chest mucus doesent like to come up a tickl and cough im 17?