Sometimes while sitting usually it will feel as if i am falling forward and i will pitch forward. i can't stop myself. it lasts 2-3 seconds.?

Vertigo: The sudden sensation of movement is called vertigo. There are several causes, most of them benign. A sudden sensation of movement when your head is in a certain position or after a certain head movement is specifically called bpv or benign positional vertigo. But you should be evaluated by your physician to be sure there is nothing else going on.