Unfortunately, you most likely have your Mom and Dad to thank for the condition of your neck (genetics).
A 4 level ACDF requires a significant amount of retraction of the esophagus which is why I tried to limit my ACDF surgeries to 3 levels or under.
The esophagus is a muscular tube, something like the belly of a snake. Imagine when a snake swallows its prey, you can see the bulge of its victim (the bolus of food) in the snake’s body. The reason the bulge moves down the snake is that the muscles in back of the bolus all relax and the muscles in front contract-propelling it down the gut.
Your esophageal muscle was retracted and muscles don’t like that. You have temporarily lost your coordinated relaxation in front of the pill and contraction in the rear of the pill and it gets “hung up” in the esophagus. This should eventually clear over time but you can deal with it now by trying to swallow the pills with a thick liquid like yoghurt. If acceptable to your doc, some pills can be mashed up in food to swallow but some can’t.
The muscle cramping is most likely from “stretching” the neck out when disc height was restored. This typically fades in 6-8 weeks, If it continues past then, consider a further workup.