Anyone else come across hand pains while playing for the day?

this morning I woke up and decided to play some simple songs today but after about 5 minutes of playing and all that the middle/back of my left hand started to hurt...not unbearable but I decided to stop playing for the day because of it.

even typing right now its a little sore but it really gets worse when I play the guitar some more.

I do lots of string bending with normal EB slinky strings

any ideas what up here?