Several different threads on here that you can search on.
In brief:
1) There should be a big red breaker button near the top of your engine - reset it.
2) Make sure that your fluid level in your trim pump reservoir is topped of.
3) Whack your trimp pump motor with a mallet, 2X4, or other suitable object (I used my boat cover pole, and my buddy used a 2X4 when it happened to him...

). Sometimes the"big hammer approach" actually works. My speculation is that the motor starts to bind up internally and may end up tripping the breaker. Giving it a tap on the sides seemed to break it loose for me and also for my buddy who couldn't raise his outdrive when coming in to beach his boat.
Erik