HELP! Dogs has lump on nose and occasional nosebleeds?

Our dog is a Golden Retriever maybe 3-5 years old. We got him when he was a small puppy and he was picked as he was the smallest, weakest looking pup (probably the runt of the litter) and we wanted to look after him.

After a few years he started to get this lump on his snout. It is not obvious as it's below the fur it simply looks like the area is swollen. It got fairly big but still not enough to look like he's deformed or anything. We went to the vets and he got it removed and also started to take a quarter tablet of some kind of steroid with every meal.

Eventually it went away but as of recently we believe it's coming back. In addition to the lump he has had 3-4 nosebleeds over the past month or so (that I have noticed) where his nose is pouring out a noticeable amount of blood. The dog doesn't seem in pain or anything and simply licks it away, however he does seem to wince when you try to wipe the blood off.

Other factors that might be important that I have noticed...for as long as I can remember (probably more recently) he has breathed heavily, usually panting even when he hasn't been for a walk (he is walked everyday, twice a day though maybe about 1 mile each time?). He also snorts and it sounds like there may be something in his nose. Also when he is excitable sometimes he starts to sneeze a lot.

The other worrying thing is his stomach. Our dog looks slim and healthy and he is playful and alive, nothing seems off. However his stomach is noticeably bigger than any part of him, it isn't fat but rather seems like it's full up with a gas or with a liquid. It feels hard and swollen and it never goes away.

According to my dad the lump was a cause for concern and the vets were surprised he'd lived this long? I don't know what's wrong with him but we all love the little guy and don't want him to die anytime soon as he's not old at all.

My main idea about the lump/snout issues is that possibly while we removed the outside lump, it may have continued to grow inside his nostril which is causing the bleeding and breathing problems?

Any info, advice or stories of similar issues would be life saving (literally for little doggy).

TL;DR...Dog has nosebleeds, lump on nose but was removed, takes steroid pills for lump, breathing problems, swollen stomach.