Random Chest Pains Late At Night ?

So, Sometimes, late at night i get theres sharp, annoying chest pains slightly on the left side of the centre of the rib cage... Weirdly enough they only happen when its reeeeally late, say 1-3am they start, depending how sleepy i am. From these i'm a little worried due to my weight problem. is it anything to be worried about? and if any other symptoms start to occur, what should i be looking out for, and when should i go see my doctor about it?