Hi Dr. Question: Could A Situation Where I Have Abrupt

Hi Dr.
Question: Could a situation where i have abrupt onset fever and chills at night be a cardiac problem?
Background: Overall, i am in good health. Well, i'm fat, but i'm active in my overweightness (30 min+ 5 days per week, at least). Over the last few months i have had episodes at night where i abruptly develop a fever and chills with much shaking. These last anywhere from 45-90 minutes. The "big" joints are very painful during these episodes. It is like having an instantaneous flu. Once all this is over, it takes me several hours to get back to feeling normal. I have tried to narrow down possible causes, including food, vitamin supplements, air circulation in the room, etc. I can't find any commonality in the time before this happens.
Assorted vitals: Normal pulse 68 bpm, usual bp is 120/80, age 55, female, take OTC Nexium and vitamin supplements. 5'7" tall, 255 lbs, minor physical issues with heartburn and osteoarthritis.
Thanks!