What exercises were you doing ? Was it tricep exercises by any chance ? And when did you start feeling pain during or after ?
You may find by the time you have read this (assuming tomorow) You will have a bit more movement...
So you're palms were facing you ? Not away from you ? Like a bicep curl ? with an isolation type pad ? -If you're palms were facing you Id say you may have damaged the tendon that connects bicep to elbow ....Can be down to poor technique,not warming up or just bad luck !Get some Ibruprofen down you , ice on the area where it hurts if it still hurts on Saturday morning seek pro' advice mate ! - dont hold me to above i could be wrong ;-)
have you just started proper weight lifting? when i was in my early stages of hitting the gym and lifting weighs i used to get really sore muscles after and some times i could not open my arm up straight i had to walk around looking like i had MASSIVE muscles with ym arms bent *text deleted* but i dont u might jsut have sore muscles from your work out