He notices that his wrists are stiff and very sore

Farhad begins typing his term paper on his new computer early one morning. After 8 hours of typing, he notices that his wrists are stiff and very sore. The next morning, Farhad begins to finish his paper, but soon finds his wrists hurt worse than last night. What is wrong?

Alexis grinds her teeth at night when she sleeps, especially when she is stressed. One morning she woke up with extreme pain in her jaw muscles, a popping sound when she chewed, and joint stiffness. How do you explain her condition and how is it treated?