<s>[INST] hi my 60 year old husband has sudden stiffness and pain in both hands, He cannot open or close them without great effort. This has happened in the past and stopped after applying a heat pad. Since it is both hands at once, I wonder if it could be a symptom of something serious [/INST] Hello, Possibilities are:- Carpal spasm or tetany-due to hypocalcemia. Go for serum calcium and serum 25 (OH) It D level Reynolds phenomenon on cold exposure-as improved on the application of heat pad. Myotonia-Exposure to cold causes marked myotonic in the exposed muscles; the relaxation of the muscle is impaired following a contraction of the muscle. Hope I have answered your query. Let me know if I can assist you further. Take care Chat Doctor.  </s>