How do you tell if you have fluid in ear from cold or something worse like menieres diease? no pain, no vertigo, just like popping/clicking

Eustachian tube dysf: The most likely thing you have is eustachian tube dysfunction, most likely from a recent cold or allergies. If your hearing is decreased you may have fluid in the ear. Try to pop your ears by holding your nose and blowing hard. The ears should pop. If you pop your ears regularly this problem may resolve on its own (30 or more times a day). If you can not pop your ears than have a doc check.

Vertigio: Ménière's disease has most commonly vertigo spells, ringing in the ears and hearing loss on the affected ear. Clicking sounds are not symptoms of ménière's disease.

Menière's : Sometimes is very hard to sort out menière's disease from other ear conditions. Menière's causes vertigo and dizziness, is associated with dampening of sounds in the affected ear. It is not commonly seen with popping or clicking sound. Sometimes responds to low salt diet and good hydration.

Symptoms.: The vast majority of clicking / popping is indeed due to the eustachian tube. This may be from an acute process such as a cold or more chronically from "eustachian tube dysfunction." meniere's disease is a whole different animal. If you have some mild vertigo that comes on acutely with clicking and popping you are more likely to have a viral illness.