The Muscles In My Upper Back Are Very Sore; The

the muscles in my upper back are very sore; the achiness goes over my left shoulder and near my collar bone. the area to the left of my collar bone looks swollen and is tender, like a swollen gland. I recently went to the southwest and went to the desert museum, but not out of the country. i developed a sore throat and swollen glands a few days after coming back and they went away; then my lower back started hurting and the pain seems to have radiated up. Not sure if my chair is just too high (which i think it is) but the swollen area next to my collar bone makes me nervous.