Extreme discomfort, possible fat necrosis & oil cyst in breast after fat transfer, options?

Your surgeon is responsible for the outcome of the procedure. Your state Medical Board should have a publicly listed address for your provider.
Since your surgery was four years ago at this point you’re probably just as well to find another plastic surgeon.
Other than examining your breast probably an ultrasound would be appropriate. Most plastic surgeons don’t do this but being present while the ultrasound technician does the ultrasound and seeing where oil cysts are located specifically and then marking them with a sharpie is not a bad idea.
If you have oil cysts then those should be drained.
Your plastic surgeon could do that if the cysts are marked or perhaps an even better option is to have a consultation with an interventional radiologist.
The first step is to make a diagnosis and that then determines the treatment.
Delivering consistent quality in Liposuctiona and fat transfer results is more difficult than most people believe.
Patients should carefully vet providers thoroughly and interview numerous providers before choosing anyone surgeon for these type of procedures.
Try to find local plastic surgeons who have a lot of breast fat grafting experience.
You may have to consult with a few of them.
Schedule all consultations as in person consultations avoiding virtual consultations whenever possible.
Best,
Mats Hagstrom MD