There could be a piece of feed possibly stuck in the throat. I would offer fluids often to see if it helps, and watch for any other symptoms. Let her drink on her own since trying to force feed anything can cause choking. Since respiratory diseases can be from bacteria, virus, or mold fungus...
Chicks who have been exposed to a respiratory disease through their hatching egg or from a carrier, can develop symptoms at that age. Is there any sign of bubbles in the eye or swelling of face? Make sure that bedding is clean and dry and provide good ventilation.