Heart typically in 60s and 70s, but last few days been 90-110 at rest. had a sore throat and stuffiness the last few days, but hr remains high and no fever. even at night when typically 50-60, it has been high 70s-80s. why thr sudden increase?

I assume you're not taking stimulants or medications that increase heart rate. No excess caffeine or alcohol? Fever has been ruled out as a cause, but an infection in your system can be the cause. Overactive thyroid is a possibility. Chronic stress or anxiety a factor? No known heart issues? Get an examination and appropriate testing from your MD or a cardiologist.

As Dr Colantino said, there are many things that can raise your heart rate. Because this has happened over the past few days, it is likely that this is related to recent events. An underlying mild viral infection could be the cause (even without fever). If that is the case, it will get better over time by itself. See your MD if the heart rate remains significantly elevated for more than 2 weeks.