How To Cure Elbow Pain?

Hello, recently I have decided to join the marines and working out for pre-boot camp is a bit rough since I haven't worked out for a while before now. On both sides of my cubital fossa my muscles are sore and on the lower part there is a ribbed like feeling under the skin. It's also rather hard to straighten my arm. Should I keep trying to stretch my arms out or just let them stay bent for a while?