Chest, shoulder, neck pain

Hello.

about 2-3 months ago I started getting a pain in the middle of my chest whenever I would get tired. I didn't pay much attention to it since it wasn't a huge pain and it went away after 20 or so minutes. Slightly more then a week ago, however, this pain started happening all the time almost. It would mostly manifest when I would bend down to pick something up or when I breath in heavily. The pain isn't only in the chest, it's also sometimes on my left shoulder, beneath my left shoulder, my lower neck, my upper back etc. Yesterday, most of the day the pain was gone. I was glad, but it came back suddenly after I ate I think. It was worse then ever, just a slight move triggered a stabbing pain in all those areas almost. When I lay down, in most positions it was unbearable, unless I was sort of sitting/laying. I had to take very shallow breaths, anything bigger then that would make the pain even stronger. When I get up after laying down, the pain would go away, but only for about 15 seconds, and then it would come back. I struggled for about two hours to fall asleep, but I somehow managed to do it. When I woke up the pain was still there but much more bearable. I took an aspirin and it almost went away and now I can only feel it on my left shoulder and when I take a moderate heavy breath.

Now, I'm not even sure this is a heart problem, but I am just worried because my father died of a heart attack, so I guess that puts me in a risk group or whatever. However, I am only 19, so I don't know if it can even be a heart problem. I called my GP (tried to call), but he is on vacation for two weeks.. What do you think I should do?

Thank you in advance.