I have a Chihuahua and is just a little over ten months old, but she has been scraping her bum on the floor which has her swollen and a cough!! Now she's had the cough a while but it goes away some times. She is a house dog. And is spoilt.. Someone told me she's in heat.
None of what you posted make sense. She needs to see a vet. If you don't know how to tell if a dog is in heat, then have her spayed asap. It sounds like she has several problems, and none of use on her can diagnose a problem by reading it. Go to you vet and have her checked asap.
In my dog coughing was a sign of heart problems, I wrote it off til she was 2yrs thinking it was a collaped trachea. Nope faulty heart valves. Very minor and not life threatening, but still I should have had it looked at sooner.