I gave blood for the first time yesterday afternoon, about 30 hours ago. Since late yesterday evening, I have been experiencing muscle-like pain in my left upper arm which over the last 6-8 hours has extended to my shoulder . It is really painful and I can t lift my arm without it hurting. No bruise , no pain at entry point. Phlebotomist did say my vein turned in the arm. What is this pain and what can I expect?