Pain in left chest for some months, please help.

For some context, i'm 16, 4'10 ft and 50 KG. I eat junk food almost daily (tho I've given up some completely) and I'm not physically active. I also have a history of terrible stomach in general (just in case it's relevant).

For a few months now I've been experiencing chest pain that comes and goes irregularly. At first it was on my right chest, sometimes dull or sharp. I remember two occasions when I was laying down, it was so painful I thought I was going to die, but it faded when I got up. My parents blamed it on my stomach issues and dismissed it.

For about two months or so, the pain has shifted to the left side, so I'm not sure if it's a problem with my heart or stomach. It usually occurs few times a day, but it's often bearable though worrysome. Then suddenly, like every two or three days or if im unlucky, in the same day, the pain is more noticeable. The pain is either dull or sharp, often directly on my left chest. On quite a few occasions, I've also experienced similar pain in my arms, legs, jaw or occasionally around armpits, which is why I'm worried it may be concerned with my heart.

I also experience headaches, nausea and dizziness sometimes, but my nausea has been there since my stomach issues and i also have a bad sleep schedule. But I wanted to mention it in case it could be related. PS : If I lay on the left side for too long, it feels uncomfortable and eventually slightly painful. I also haven't gotten it checked at the hospital due to lack of money and equally unhealthy family members, so I have no test results or anything yet.

I understand that seeing a doctor is the best case but my financial situation can't keep up right now. If possible, I'd appreciate some advice on how to perhaps ease it or what the potential causes could be. Thank you !