Sometimes i feel like my knee was pricked with a needle and then my foot jerks right after. is this normal? what could be wrong?

Likely Normal: This is likely the result of normal episodic nerve stimulus that can happen in healthy individuals from time to time. It can also result from a pinching of the peroneal (or fibular) nerve based on certain postures or leg positions. If you experience prolonged nerve-type pain, or weakness in the leg, or the current symptoms worsen, I would suggest an in-person exam.