I have never had problems with my ear before, till a about 5-6 months now. I have a muffled left ear that only clears up when I yawn which only last for a few secs. I also have nasal congestion which has me sounding as if I have a cold which I don't, I went to the doctor and they treated me like if I was an asmathic, gave me nasal spray,ear drops and some other tablets it cleared up for a while then I travelled and when I came back the same symptoms came back again. I went back to the doctor and they gave me more medication bt this time me ear is still blocked and I still sound congested. They are saying it's my sinuses that act up but I'm wondering if it's really that or something more serious.

I would suggest you see an ENT. Ears, Nose, and Throat specialist for a proper diagnosis.

40 years ago I went to 2 ENTs for this and both seemed bored by the whole thing - not interesting enough.
I did learn from one that the eustacian tube can collapse, blocking mucus from draining normally down the throat (something you don't notice). The other one told me I had a deviated septum - I didn't!

Turned out to be the last molar under that ear, which took me forever to find out, because I didn't have a tooth ache.

25 years ago I had chronic bronchitis that no antibiotic would touch. I couldn't climb stairs and was very sick. That turned out to be an infection in my jaw, under a crown.
So - two dental related congestion problems!

MAYBE
You can have allergies, different from asthma. If to dust and other household things, symptoms stay the same. Outdoor allergies to plants change.
RARELY, a sinus virus ("cold") can linger so long that bacteria move in, acting pretty much the same, but viral infections usually clear up in a week or two.

So I suggest that you write down anything you can think of that might fall into any of the above for about 2 weeks and see an ENT or demand more from your regular MD. You need to help the doctor help you. You gloss right over the mention of travel and coming back - you mean it was gone when you were gone??? THAT'S IMPORTANT!! That sounds like allergies, and there are countless allergens. Pets? Dust? Carpets and curtains? Paint? Formaldehyde in building products? Hundreds and hundreds..

And see your dentist more regularly than I did!

From what you said, I would put my money on something in your house. You said you were on meds and it cleared up, you went away and when you came back it started again. Now that winter is almost over open up the house and get some fresh air in there.