No pain, no gain. Consult your Doctor. I'm 21, weighed 185 when I started going to the gym last month. I feel all sorts of things. My chest, lower right abdominal part, that sharp stabbing feeling on the side, chins, all that **** be hurting me. But I keep running.
You gotta fill us in your body type. Like did you wrestle in high school, played sports. Or do you play nintendo all the time.
Keep your workout consistent or exceed. Walk another 20 Min for a week see what happens to your arm.