Hi and welcome to Just Answer. I am a licensed veterinarian and will do my best to help you.
Has he been anywhere unusual recently- groomer, dog park, kennel?
How much is he coughing- constantly, frequently, occasionally, rarely?
we went on a hike yesterday
its occasionally but persists when it happens
Does the cough mostly occur when he is active, excited or when he first gets up?
first gets up
from laying down
Is there any colored discharge from his nose? or is it clear?
just clear sputum when he hacks for a few
but not everytime
Most likely this is tracheobronchitis, a highly contagious respiratory disease of dog spread by coughing. Usually they feel good, eat normally but cough when they exercise, are excited or first thing in the morning when they get up.
hes still out playing with my other dog
so a vet trip?
Treatment is supportive, we may use cough suppressants like Robitussin DM, keep him quiet and mostly wait it out. If he develops a colored nasal discharge, has a reduced appetite or is coughing alot your vet will need to help you with needed medications to reduce the severity of the disease.
how long should i give it roughly
These cases frequently will persist for 2-4 weeks, with the cough getting less frequent but still coughing hard when it occurs. Also watch your other dog for signs as it is contagious.
ok thank you