as per the OPG xray provided by you,you are having 5 unerupted teeth.of that 5 teeth ,tooth number 38 and 48 have chances to erupt since your age is only 18 years...where as tooth number 18,28 are impacted and they have no chance of eruption since they are totally curved...so you need to undergo extraction of those teeth to avoid damage to upper 2nd molars...because of those teeth you are having sensitivity and pain symptoms .....and in the OPG i can see the restoration in upper left 1st molar and no cavity is present in 16 ,17 or 27 teeth...and about your impacted premolar i.e 45 ,i better suggest you go for extraction because root is highly curved or you can consult an orthodontist if by means of bracing they can save the premolar
Next Steps
if you are present near to BTM bangalore ,you can come to ADVIS DENTAL for better prognosis