Hi. didn't injure self, only worked out recently. earlier i bent arm to scratch something ,my elbow ached. , now it's about 4-5 on pain scale. ideas?

Arm pain: If there are no visible signs of infection like swelling, warmth, redness, and inability to move the joint then a septic joint is unlikely. You describe no trauma or acute event so fracture, sprain, tendon injury is unlikely. Probably post exercise or delayed onset muscle soreness. Here here is a link to a good summary of the condition. http://emedicine.medscape.com/article/313267-overview