Where about in the chest are you having the pain because that could tell you it's connected to the lungs or heart? A couple years back I had chest pain in the area of my right lung and I ignored it thinking I has strained the muscle. Wouldn't go away and then one morning I woke up and it felt like someone was stabbing my chest. Turns out I had a plural effusion due to a pneumonia infection which is fluid buildup in cavity between the lungs and ribcage and I had to have the fluid drained. I just thought my Cystic Fibrosis was given me a bit more of a cough like I sometimes get and it turned out to be far, far worse. Took me out of commission for a couple months due to multiple rounds of IV meds and just resting while body recovered.