Caffeine causes muscle tension & pain. I do massage therapy for pain relief. I try to get all my massage therapy clients off all beverages and foods that contain caffeine, theophylline & theobromine.
For many people, it makes the difference between being in pain, or not. Cutting down helps, but not as much as getting off these drugs entirely.
Chocolate is the worst one for causing pain. Chocolate contains caffene & theobromine: tea contains caffeine & theophylline. These are related substances, all are toxic, all are addictive, all cause muscle tension & pain.
These are harmful drugs, not health foods. Please see: