Unfortunately you probably pulled the muscle near the Tendon. The tendon is what connects the muscle to the bone. Unlike muscle injuries which heal in a month or two. An injured tendon may take up to a year to heal. The reason is, the muscle receives blood supplies, but the tendons receive far less. Blood heals it brings nutrients and takes away toxins. I would advise moist heat and definitely stretch (no bouncing) at least 15 minutes before doing any type of physical activity.