if your muscles are just sore from overtraining: suck it up.
if you actually pulled a muscle, that's a tear in the muscle. Its only going to get worse until you take time off to rest it. Think of your muscle as a rope...the more you use a damaged rope, the more it frays. you need to stop, fix the rope, then get on with life. same with torn/pulled muscles. you have to stop and let them heal.
Ice an injury first, to keep swelling down, twenty minutes on, twenty minutes off. After 24 hours, IF there is no new bruising, you can stop icing. If there is still new bruising, keep icing. That means that the injury is still bleeding. Once the injury has stopped bleeding, then ice won't do any good.
to keep things from stiffening up...jacuzzis are always good. Heating pads work well too.
sigh...after 13 years of karate and 6 years of ballet, I've learned WAAAAYYYYY too much about injuries.