Isa Herrera wants to help New York women find their inner “goddess-ness.”

“I am the secret to a better sex life,” said the 55-year-old.

Herrera is a pelvic therapist — a physical therapist who works to fix overactive and underactive pelvic floors via internal vaginal massages.

“I put my finger into the vagina and press along the walls to the first knuckle to find where the issue is and treat it and then go deeper to the second and third knuckle,” she said.

Sounds personal? It is.

Elizabeth Haag says the first thing male friends ask when she is brave enough to tell them about receiving pelvic therapy is whether or not she orgasms during treatment.

“It’s always the first question I get,” said Haag, a 30-something Park Slope resident who owns an events company. She was prescribed therapy seven years ago for a pelvic floor dysfunction.

“I couldn’t walk or exercise or sit or wear pants,” said Haag, who suffered from tightness after breaking her tailbone. “I was dating someone and we just stopped having sex because it was so painful.”

Although she admits she found her first few appointments “strange” due to the intimate nature, Haag has never been aroused during therapy. “It’s so antiseptic. It’s not sexy at all,” she said.

According to a Duke University study, the number of women in the US suffering from a pelvic-floor disorder will increase from 28.1 million in 2010 to 43.8 million in 2050. Earlier this year, “Girls” actress Lena Dunham wrote in an essay for Vogue that she had tried pelvic-floor therapy to alleviate the extreme pain caused by endometriosis.

An overactive pelvic floor can lead to tightness, while underactivity can cause incontinence and prolapse, a condition where organs slip out of place.

“They run a freaking marathon and their organs fall out of their vagina!” said Herrera — who charges $590 to $750 per session — of some patients.

When Herrera founded her Midtown practice, Renew Physical Therapy, in 2004, there were only four or five other pelvic therapists in the city, she said. Now, Amy Stein, founder of Beyond Basics Physical Therapy in Manhattan, estimates that there are 30. Both see about 20 pelvic therapy patients a month.

(Therapists interviewed for this article also treat male patients — rectally — for incontinence and erectile dysfunction.)

Pelvic therapists must have a physical therapy license, and certification classes are available. In California, it is legal for “sexological bodyworkers,” like Kimberly Johnson, who calls herself a “vaginapractor,” to touch patients’ genitals without a physical therapy license.

Johnson, who is based in San Diego, maintains that she’s never had an issue with a client becoming aroused during treatment.

Herrera agreed, adding that while patients may feel “sensations,” the real arousal happens later. “It wakes them up a little bit so they can feel more when with partners, not during treatment sessions,” she said.

Dr. Elizabeth Poynor, a Manhattan gynecologic oncologist, says, despite initial skepticism of the treatment several years ago, she now regularly refers patients to pelvic therapists. “It’s a bit more of a proactive approach to women’s pelvic health,” she said.

Herrera — whose calendar is booked through April — blames the growing popularity on urban life. “People in New York, their vaginas are too tight,” she said. “Everyone is so stressed out in this town.”