Would it do any harm trying nasal irrigation?

I have an uncomfortable feeling in the back of my nose above palet, and pressure in my ears and constant sinus pressure and ear pressure, the ear pressure gives me tension like headache, had this for over 2 months now, had same thing last year around spring summer where it gets worse.

My head is buzzing, sometimes I get out of the blue lightheadedness where the volume goes down and ringing and feeling like I'm going to faint. Only lasts a few seconds.

I find it hard to think, when I think my head aches, or my pallet.

I had nasal sprays twice from the doctor and was told there's a lot of fluid in my ears. It didn't work.

It's worse when i lie down at night, my nose blocks up.

Would it do any harm?