Have had trouble swallowing for a year, then came cough & stiff neck. Now a lump on my collar bone, size of a grape &moves. I don't have acid reflux.

Get assessed. You should get assessed by an ENT to check the swallowing dysfunction, as well as the other associated symptoms to rule out any concerning issues like esophageal cancer. Isolated swallowing dysfunction for a year in a young person that smokes cigarettes should be assessed to be safe.
Swallowing dysfx . Swallowing problems do not cause a lump on the collar bone. You should get a swallowing test and see an ear nose and throat doctor who will make sure the lump on the collar bone is not a lymph nose or a mass. A grape size lymph node is probably reactive and nothing to worry about. Good luck and good health!