First there is NO dumb questions.

Second, I see no issue using a pre workout and clen. If u can handle the sides.

Clen will have u sweating like crazy, shaking, great stimulate. Add some pre to that and u might find your self laying in a cold bath trying to slow your heart down from your chest. Haha not to mention then shakes like I said before.

All in all there is no need for a pre of u us clen. Clen is so strong u won't need anything else