The situation you describe sounds very unpleasant! In general, there are several different things that could be contributing to your symptoms (and ultimately, you should see a physician about this to start figuring out what is going on). There are muscles that help you swallow and that contribute to elevating the palate, moving the tongue, and generally allowing the normal swallow and cough mechanisms that help us keep food or saliva from getting stuck. It is certainly possible that you may have a weakness in one or more of these muscles (from either a muscle or nerve problem), leading to an impaired swallowing mechanism. However, such disorders would be relatively uncommon in someone of your age, especially without any prior surgeries, radiation, or other health issues and symptoms.
Sinus congestions and allergic symptoms can also cause constant post-nasal drip of mucous/phlegm that can be quite thick and bothersome. Even if you are able to mobilize these secretions, they can also cause a constant cough/tickle in the back of the throat. Furthermore, if you never had your tonsils removed as a child, it is quite possible to get food or mucous trapped in the tonsillar 'crypts'...this is also a very aggravating feeling that causes a sensation of needing to clear the throat. Finally, gastric reflux disease can also sometimes result in symptoms similar to what you describe.
The bottom line is that you need to sit down with your primary care physician
and go over your symptoms in great detail and have said physician do a careful exam of your head, neck, and throat to decide on the next steps. You may need to start some new medications or see a specialist, likely an ear-nose-and-throat (ENT) physician.