The pain you have described is it really pricking or heaviness? Does it increase with breathing or coughing? Is it there whenever you are excited or exercising?
If it is a pricking kind of pain more during breathing and last for about a minute then it is probably related to your lungs
If it is during exercise or heavy, crushing kind of pain it looks like its your heart. Ideally you can get an ECG done and find out if there is any problem with your heart. and get a Chest X ray
to rule out lung disorders.
Considering your age and no family history of heart diseases you dont really need to worry too much.
Cutting down on coke is a very good idea and keep consumption to a minimum.
It may also be a very simple condition called "Precordial catch syndrome" which is typically pricking lasts about a minute or so and more on breathing and relieved on its own.
Hope this helps. Take care.