Lifting heavy things , most of the times do stiffness
in the back of neck. Its very unusual that front of neck is having any sort of stiffness. but possibility can not be ruled out. As You are smoker so there might be some other problem too and by doing heavy work it gets in to mind too. We can say sirendipity. You should thoroughly checked up by ENT surgeon or gen surgeon for throat. Take a NSAID
and Muscle relaxant
for 3-4 days. If you get any benefit. But meet ENT or Gen Surgeon on priority bases.