Thanks for writing in.
The fact that you had marina coil earlier too and got it replaced rules out any adverse reaction to the coil itself. You could also get an ultrasound
scan to be sure that the coil is in place.
Since you have had kidney transplant
, your immunity may be little weaker than in normal individuals.
Fungal infections are not picked up on routine sexually transmitted infection tests.
This can result in fungal infection in your vagina which is causing the irritation.
I suggest you apply some antifungal medication as suggested by your gynecologist.
Hope this helps.