I have issues with feeling in my left hand and have a large bump on the top of my hand when i stretch it, is it worth getting checked out?

Bump on hand: The most common cause of a 'bump' or lump on the back of your hand is a 'ganglion, ' which is a cyst coming out of a tendon. These usually do not hurt unless they become large and tight. In the old days, people used to smash these with a book ('bible ganglion') to pop them. It doesn't need attention unless it really bothers you. Sometimes they go away by themselves, or get better with a steroid inj.