"cold symptoms"? March 5-7 -3 days

Fergus developed repeated sneezing, then 
day 2-3 some cough type respiratory thing, with 
1-3 second "forced coughing-wheezing"
He's alert but seems to lack his usual endless 
energy and stamina.
We are concered he may have an obstruction or infection in respiratory system.

He does have a strong prey drive, always sticking
his nose in everything, and will pick up nearly e
anything on daily walks. He'll "drop it" but it's hard to 
maintain 100% obedience with that.

Symptoms:

Sneezing
Cough
wheezing
long cough/wheeze 
lack of stamina

Urination and defecation OK, sleeps without difficulty, good temperment.