One of reason of this kind of sensation is pelvic floor problems and weakness. One of the cause to be considered is levator ani syndrome. Ask your physician to consider this entity and get the following investigations;
2) pelvic MRI
3) nerve-conducting velocities and needle-electromyographic studies are used to help evaluate compression or entrapment neuropathy and pelvic floor function.
The treatment is following;
1) electrogalvanic stimulation,
2) biofeedback training,
3) digital massage of the levator ani muscles
4) sacral nerve stimulation
5) physical therapy for the pelvic floor muscles
Pelvic congestion syndrome, Pelvic floor relaxation disorders, Pelvic floor dysfunction too need to be considered for the vaginal tingling. Though treatment is essentially same.
The other diagnostic consideration would be;
1) Pyriformis syndrome
2) Pinched nerves in back.
3) Neuropathy due to other causes.
4) Pelvic inflammatory disease
Investigations to diagnose the above would be lower back MRI, glycosylated hemoglobin, vitamin B 12 levels etc. You may start multivitamin supplements and probiotic meanwhile.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.