Becky, I'm not a fan of putting thread in the freezer only because I'd be worried about moisture from the thread getting into the inner workings of my machine and creating other problems. However, I have known people to have problems similar to yours in the winter when the air in the house is drier because of having to heat the house. Putting a small humidifier in your sewing room, if your place is too dry, may be the solution you are looking for. My sister was having problems with her machine (she has a wood burning stove in her living area and the dry heat was circulating up to her open-space studio) but when she put a humidifier up there, she had no more problems with her machine. She only experiences problems in the winter.
I also found this URL that supports this idea:
http://www.emblibrary.com/EL/elprojects/Projects.aspx?cs_productid=pr1702 and paragraph five supports the idea of using a humidifier in the winter. This article also offers other good advice for problems with embroidery so I thought you might like to see it.
Wishing you a quick resolution to your problem!