hi
thanks for the query...

firstly you should get the treatment for inflamed area... ask your dentist if your posterior area need scaling and root planing...

use ultrasoft tooth brush and desensitizing tooth paste twice daily... desensitizing tooth paste should remain in contact with your tooth for atleast 2 mins... and you can use desensitizing mouth wash after that...

massage the area by chlorhexidine gel twice daily to reduce gum inflammation...

also check for any cervical caries and get it filled if any...
take care...

Thanks for the query. Hypersensitivity near the gum line while taking cold liquid or brushing can never be related with sinus problems. It is a clear sign of dentin or cementum of tooth root exposure. If dentin is exposed vibration of nasal blowing may also hurt you in that area. You have to be re examined by a dentist, not only for dental caries, but also for any horizontal cut on the tooth surface parallel to gumline ( abrasion), enamel chipping, slight root exposure under the gumline. Even a small developing dental caries between two teeth may also cause such problem. A bite-wing dental radiograph can diagnose that dental caries in between teeth. Please re visit your dentist. I hope he/she will find out the reason of your "pain sensitivity". Thanks.

Hello,

Thanks for writing to us.

The pain sensitivity in upper left molar can be due to bone loss or periodontitis of the inflammed tooth.

Get a deep scaling done.

X-ray of the tooth will help to find out any infection underlying.

Meanwhile,maintain oral hygiene well.
Brush and floss your teeth daily.
Take care.

Hi
Thanks for the query
You are having tooth sensitivity and pain because of gum disease.
Consult a dentist for scaling and polishing.
maintain good oral hygiene.
Take care