Yesterday When Lifting A Tree Limb My Left Upper Arm

Yesterday when lifting a tree limb my left upper arm muscle made a crack noise and a pain ensued but shortly the pain went away. At bed time I noticed a swelling in the muscle. Early this morning a small bruise like color appeared and got darker and larger until half the front of my arm is black. I have been treating it with cold packs. Is this something that needs medical treatment soon?