If the pain is your normal, achy, stiff pain, heat works better.
If you're an athlete, or exercising, heat before practice or performance helps warm up the body. It assists in getting the body prepared for the activity and demand on the muscles, ligaments, joints, etc. You can then, ice afterwords to control the inflammation caused by the activity.
So just remember, when the pain gets worse, ice. If It's the every day stiffness, heat.
And as always, if you have questions or concerns, don't hesitate to contact me.