One other idea: Where I am, CVS pharmacies now have nurse practitioners at some of their locations. If you are so lucky, that's another option.
With a fever that high, I would suggest you see if you can see a doctor tomorrow. Your primary care doc or urgent care. Call PCP early or for urgent care, get there when they open.
Could be flu ,,if pains continue and you feel concerned maybe good to have someone look at you..Its hard to tell what it may be ..go with your gut as far as the ER Good luck hope pain eases soon