I know what you're talking about because my wife did shockwave treatments for her shoulder. I then learned more about it and discovered it is also used for ED. For $2400 you could also buy the equipment yourself. I did discover late to the game that vacuum erection devices, especially using pulsed vacuum, did help with recovery of those smooth muscles that have been traumatized, and I could see that by extension high frequency vibration could also be helpful. What gave me pause, though, about both shoulder and ED treatments, is the idea that high frequency vibration had some sort of unique benefit. (What makes it "shockwave" is that it is sonic or ultrasonic in frequency. An example of sonic would be 1000hz/cycles per second, ultrasonic might be 15000hz.) These frequencies may have unique benefit, I just didn't see any evidence that assured me that was the case. The treatments are marketed, like other forms of off-label treatments or therapies, by testimonials and personal recommendations.
So, being the skeptic that I am, I tried other forms of vibration on muscles, including the particular ones in question, such as that provided by a vibrating trigger point dumbbell https://www.amazon.com/dp/B07GFMPSBM. Apparently "vibrating foam roller" is a better search term. My own experience suggests to me that vibration is helpful and high frequencies are helpful, even though they are not considered proper practice of physical therapy (and hence are not reimbursible by insurance).
I would add that it can easily be too much, and hence the protocols are very careful to limit the amount of high frequency vibration during any treatment session. (LOW Intensity Shockwave Therapy.)
I still use the vibrating foam roller on various muscles, but not on the muscles in question. I found the "treatment" there too high intensity. Maybe I should (carefully) try it again.
Here's an example of the shockwave equipment to give the idea. This is just an example. https://www.amazon.com/SHEYERA-Shockwave-Extracorporeal-Non-Invasive-DR-88/dp/B0FQ4QXGZR/