Thanks for the query.
The irritation and pain you are having could be due to small abrasions because of intercourse.
If these abrasions get infected the symptoms will intensify and prolong.
The discharge you are having could be a side effect of the pills.
While being on hormonal
pills, some amount of fluctuation in the hormonal levels is common and that can lead to irregular spotting.
This will subside soon.
If vaginal itching
etc persists better to consult gynecologist once and get examined.
Sitz bath can give some relief.