Are there any safe pain relievers like for muscle pain relief which I can take with warfarin?

You will basically want to avoid steroid drugs, acetaminophen, allopurinol, aminogluthemide, antibiotics, antiarrhythmic heart drugs, androgens, antacids, antifungals, antihistamines, aspirin, antidiabetic drugs, disulfiram, barbituates, benzodiazepine, tranquilizers, calcium supplements, chloramphenicol, cholesterol lowering drugs, or NSAIDs.

I would think possibly acetaminophen would possibly work. But I would consult your doctor. I'm pretty sure analgesic drugs like acetaminophen would collide with anticoalugents like warfarin.

Yes, you can safely take acetaminophen (Tylenol) while taking warfarin. Acetaminophen with codeine is also safe if you need stronger pain relief.
You must avoid aspirin and other NSAIDs including ibuprofen and naproxen as they can increase the risk of serious bleeding.
You may also be able to try a new class of anti-inflammation drugs called cox-2 inhibitors. Cox-2 inhibitors appear not to carry the same risk of serious bleeding. Examples are Celebrex and Vioxx. You would need to check your INR levels frequently.
Talk with your doctor or pharmacist for more advice.