No cure so you gotta rest. Nose is stuffed so you gotta mouth breathe. Throat is dry from mouth breathing. Dry throat makes it painful to swallow. Pain keeps you from sleeping and recovering. Lack of sleep leads to worse symptoms like piercing headaches. Need to rest to get rid of the headaches. Headache and swallowing is too painful to rest properly. Lack of rest perpetuates headaches, nose congestion, dry throat, painful swallowing.
What is this BS
this sounds alot like nimbus variant, covid than a cold. i had it recently and i had the symptoms you described, the painful sore throat, swallowing, the headaches though not a s severe as yours. bronchitis as well.
a cold causes alot of sneezing, and a mild sore throat at most, plus congestion in the nasal area. it almost never causes painful sore throat, and the coughing /bronchitis usually occurs after the fever, and when the cold resolves.
with covid you coughing/bronchitis right form the start of the fever. i couldnt swallow food or water for a few days, but i was hacking/coughing thick sputum for that long.