pain flashes in elbows

Hi Dr 8a, I´ve climbed sport routes for over one year now ; I usually train with friends at a little private bouldering wall,where until now I used to train resistence for routes. However,since they got me into Bouldering,I also tried training bouldering with them (they are undoubtely better than i am). I´ve quit training resistance in the gym,and for the last two to three months, I´ve been trying to climb difficult boulder problems with them,mostly four to five powerful moves (after 20 min warming up with light climbing).   The problem came 3 weeks ago,when I began feeling this flashes of pain,to call them so,in my elbows. It´s not a permanent pain; it dissappears when I´m home or so,but when I do this powerful moves it feels like stings in my elbow. Sorry,I don´t know how to describe it better,just as stings or flashes of pain in the elbow bone. It feels allright when I climb light routes,but when it comes to doing something "hard", feels like stings.       Do you think this may be tendinitis? If not,what do you think it´s the problem? And what would be the sollution?  Many thanks beforehand !  Alex