Yes, PILL is a Scrabble word!

Letter values in Scrabble US: P 3, I 1, L 1, L 1.

Is it a valid word?

PILL is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

something that resembles a tablet of medicine in shape or size
a dose of medicine in the form of a small pellet
a unpleasant or tiresome person
something unpleasant or offensive that must be tolerated or endured
a contraceptive in the form of a pill containing estrogen and progestin to inhibit ovulation and so prevent conception

Also: birth control pill, contraceptive pill, oral contraceptive pill, oral contraceptive, anovulatory drug.