[Curious] The foreign body sensation felt in the throat? Feeling of something caught?

These days, I often feel like there's phlegm stuck in my throat. I keep experiencing a foreign body sensation as if something is caught, but it doesn't cause much discomfort in daily life. However, there are days when this discomfort and foreign body sensation are particularly severe.

Because cold water is not good, I intentionally drink lukewarm water at 40 degrees Celsius often, but only at that time, and soon I feel the foreign sensation again... Once, my father-in-law took Yonggaksan, and I thought, "Oh, that was it," so I bought some at the pharmacy and tried drinking a whole pack, but I didn't notice any special effect.

Also, I tried other products similar to Yonggaksan based on the pharmacist's recommendation, but they only worked temporarily; the fundamental problem wasn't solved. When I visit the hospital for a check-up, they say they don't particularly see any phlegm or anything, so why do I keep feeling this foreign body sensation?

Are there any diagnoses, effective treatments, or folk remedies that you have received or tried for symptoms similar to mine?