Pain on lower left neck and left side of face slightly weak?

Face weak.: Lots of reasons for neck pain but if the left side of your face is weak then you need to see a doctor right away. Weakness in your facial muscles is not normal and could be signs of a stroke. There are other causes but you should be seen soon. Bells palsy can also present as weakness. Either way you need a doctor to evaluate this and right now. Early detection is very important.