it might be "morning stiffness", if it lasts longer than half an hour, be careful of SLE, RA or something in that category. watch photosensitivity, raynoid's sign, oral ulcer, joint pain, esp knees. fever/chill, rash, etc. if more than 3-5 are positive, then go to see a doc and do a screening test like ANA, RF, anti-Sm, anti-dsDNA.