I have off and on swollowing problem for close to 3 years. sometimes for weeks all is normal. i also have middle chest discomfort for a long time now. is it most likely jackhammer esophagus or something serious?

Need to examine: It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. You may have gastro-esophageal reflux and should see a GI specialist. If you are overweight, losing weight will help. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs.