Thanks for posting the query,
As you told your molars on the lower right side are extracted few months back but you still have pain and swellling on the same side.
I would suggest you to visit to an Oral SUrgeon get an examination done ,
Take an OPG x-ray , it will give you the periapical condition of the tooth. depending upon which the treatment will be decided.
Pain can be because of left over tooth particle , osseous lesions , bone infections or some neoplastic lesions .
You take antibiotic and analgesic
Yse lukewarm saline gargles 3-4 times a day this will give a soothing effect , use antiseptic mouthwash gargles to prevent infection and promote healing .
Hope this helps out.