How can I make my body joint stiffness go away with yoga or tai chi?

Either. Both are excellent to work with. I like yoga due to the stretching and balancing component. Patients who have more neuromuscular problems, dizziness issues, back problems find tai chi more helpful. I would try both out and see if it helps. Also drink more water since dehydration from caffeine, not enuf water makes the joints hurt. Use glucosamine and curcumin for joint pain.