Dull ache over heart

So I've been freaking out over potentially having heart problems for about 2 weeks now(I do plan on going to a walk in clinic in the morning). The last two days I've started feeling better and almost considered calling off the trip.
Well a few hours ago and new problem decided to show up and has me freaking out again. Whenever I swallow there is a dull, pulling ache over my heart. Kind of like a strained muscle feeling. I don't feel it as much when I hunch over. I googled this symptom and (of course) I am instantly met with a warning saying to get immediate medical attention.

Since I only feel it when I swallow does that mean anything? I have no other symptoms at the moment, and my heart rate seems normal. I did have a headache, but I turned out the lights and took some ibuprofen and that's gone. Previously over the last few weeks I've had shortness of breath that sometimes got worse when laying down, but for the last 2 days I've been feeling pretty good.

I'm so tired of this constant fear that I'm going to have a heart attack and die, I can't wait to get this checked out tomorrow, but I'm wondering if I should go to an ER now. I don't have insurance though, so I would feel silly if I went in for the one symptom and they said it was nothing.

As long as there is an internet connection and google the "what-ifs" rage on lol. I know it would be really odd for me to have a heart attack at my age, but the idea of being that 1 in a million freaks me out.
You have helped, though, and it makes more sense that the pain has something to do with my esophagus.