What breed is your dog and how old? These sound like swollen lymph glands which could mean infection or other things you don't want to hear. It is possible they are getting so big they might be starting to close off his trachea. Yes, you do need to monitor him and, if that gets worse, you need to get him in! Any other areas of swelling like in his armpits or groin area? When he lays down, try to keep his head elevated and extended. You might try using a humidifier near him. I would limit activity to just going out to potty. Sounds like he really needs to see the Vet fir an evaluation and some testing. Please come back to update.
Does he have a temperature? If so, how high? A dog's normal temperature can range around 101-102 Do you have a thermometer which is safe to be inserted anally?
If his temperature is high, the best plan is to get him in to see the emergency vet, even though there is an out-of hours charge on top of the fee. If you can do this on credit card or overdraft at the bank, that is better than the pain you would feel if you didn't and he needed help.
Pneumonia is a possibility...especially if his temperature is high? But of course none of us here can diagnose. Only a vet can do that.
Elevating his head while he lies down might help him breathe better?