Suggest Treatment For Upper Back Pain

+Back pain came from nowhere. Upper back. For two days I could hardly bend over without feeling the pain. On the third day the pain eased its way to the front--I could not take a deep breath without feeling immense pain. I felt the chest pains from the left to the right. Yesterday I had an allergic reaction to something that I ate and was sick to my stomach for a couple of hours. Everything came up and out. Today the pain in the back and chest is almost gone. Could this have been a side affect of the flu or cold that never manifested itself? I rarely have back pains and have never had chest pains before. I will be 65 years old in February.l