Should I take medication for a lightly sprained ankle?

No. Stick to rest, ice, compression, and elevation for a mild (i.e. Grade i) ankle sprain. Antiinflammatories or pain medications only treat the symptoms and don't improve the outcome so unless you need to take something for the pain, don't bother.
Sprain. It depends on how much pain you have. Generally a md ankle sprain or grade i ankle sprains require ice only. But pain is a very subjective thing. If you have pain that you can't tolerate them you should take medication to be comfortable.