Well, vertigo is typically an inner ear issue. Sometimes not. So if your nose and such is stuffy..could be that your ears are out of whack too. I had vertigo probably 3 months. Only when laying down. If you look on you tube you can see videos on Epley maneuver. It may help.

yes

Any illness, surgery, stress, etc. can temporarily make MS symptoms worse.
Could you have a sinus infection, not just a cold? You may need an antibiotic.

I do get vertigo fairly often and use meclizine as necessary. It keeps vertigo pretty much under control.

i have r/r lately me been getting vertigo its a pain in the arse but thinking also cause i live in australia heat may not be helping me either

My wife has Secondary Progressive , She gets vertigo off and on.When she is having trouble with it ,she will sleep in the recliner for a few days in a more upright position. That seems to help..