So many pains in back, breathing and heart?

I am yes overweight, lately if I breath deeply or laugh to hard I get pain in my lower/ mid back on the left or right hand side. I also tend to get tightness in my chest or very quick sharp pains running through the chest on the left hand side. If I laugh too much/hard I can get piercing pains in my head. I know this sounds weird but this is what is happening. I am petrified of doctors, any ideas on what this could be...