I've taken Naproxen & now can I take paracetamol, how long do I have to wait b4 I take it?

For moderate pain you can take naproxen and paracetamol (acetaminophen) together. Studies have shown they even work better in combination than separately. Each medication works differently to relieve pain and they are broken down differently so there is minimal concern about safety.
Do not not take more than the recommended doses of either medicine and make sure you take the naproxen with some food.

https://www.drugs.com/dosage/naproxen.html#Usual_Adult_Dose_for_Pain
https://www.drugs.com/dosage/acetaminophen.html