One of my breat is feeling much more heavier then the other one and it hurts when I put pressure on it what can that be

It could be that you're getting your period, it could be a cyst, it could be a tumor, it could be a pimple, it could be that you're sick, it could be an ingrown hair, etc. etc. etc.

In other words, we can't really tell you. There are too many possibilities.

If you're concerned, see your doctor.