Arm soarness

Where is it okay for an arm to be soar after a good outing of close to 100 pitches. I usually get soar behind my should and down my back and some in my elbow like on the inside of my elbow… I’ve heard elbow soarness is bad but how can u prevent it from becoming soar and what does it mean if it gets soar… and also lol sorry so many question but what work outs will help with strengthening the elbow