I would recommend a clinical assessment.
Perineal and pelvic floor symptoms are common after childbirth but can also occur in women who have not had children.

It sounds like a small cyst and an ingrown hair follicle can't be excluded, but I would advise you see your GP to have this checked.

As your symptoms appear chronic and quite significant I would also recommend a gynaecological clinical assessment prior to considering further treatments.

This may be secondary to vaginal dryness and irritation. Low oestrogen levels are commonly the cause of low genital tract atrophy. Of course excluding a urinary tract infection, thrush or other vaginal infection first is recommended. If all microbiology tests are negative, and there is no contraindi...

It is important to exclude bacterial infection and anatomical causes.
Some agents used for lubrication may cause more discomfort.
If the symptoms persist despite use of appropriate lubrication, a gynaecological assessment may be indicated.

There are several possible causes, and certainly in most cases these symptoms can be effectively treated.
I would recommend a consultation with your GP for the initial assessment of your symptoms and a possible referral to a gynaecologist.

Possible causes include types of candidiasis or bacterial factors.
I would recommend a thorough microbiology assessment with swabs and treatment based on results and sensitivities.

Vaginal lubrication may also help.

The most likely cause seems to be vaginal thrush that needs to be treated. It is important that both you and your partner get treatment. In some cases, there may be anatomical reasons, that can become worse with time from chronic irritation, that can also be treated. A clinical assessment would be r...

These problems can be complex and require clinical assessment and possibly further investigations before one is able to give advice.
I would agree that an assessment by a specialist is the best way forward.