I had swelling of nasal lining a few months ago, i was diagnosed with a sinus infection and given antibiotics, it cleared up but swelling still there?

Follow up exam: Try to see the same healthcare provider that saw your infection for a follow-up review. This is a hard thing to assist with over the internet but a look and possible tests including imaging may be very useful.

Could be more..: You could still have swelling there because of chronic allergies or persistent viral inflammation. Very often sinus infections are diagnosed when in fact they are flare-ups of allergies that can cause sinus symptoms/pain. You should see an ENT to see if you need to be treated for allergies, or if you indeed have residual/chronic infection that was incompletely treated initially.