Headaches, neck pain, tinnitus and fatigue for a week. can't seem to think straight. the neck tightness & tinnitus starts first. then the headaches. it gets worse with movement and fatigue. heat helps a bit. not stressed. what could it be?

Long COVID-19 unless you have had vaccination. Were you ever exposed to someone with COVID-19 for certain.

It would be helpful to get examined, as you might require testing to check for COVID-19, but also a viral meningitis, especially if you have a fever. Not feasible to pin down further but important that this be evaluated ASAP. Contact your doctor.