I had a bad cold last week; this week I have no symptoms except for body ache everywhere still. What could be the cause? Should I keep taking pain med

Hydrate, and rest. Your body id still recovering. Make sure you eat and drink well. Rest and in no time you will be better. Its ok to take pain pills per recommendations if needed.
Seasonal flu. It is very common viral infection. Be patient. Usually the condition resolves on its own in two weeks with home care. Drink water and get a good rest. If there is no improvement or sore throat is severe or lasts longer than another week, or you are getting joint pain; see your pcp for evaluation.