I had a similar situation evolving then a cancer surgery finished me off. I was diagnosed with venous leakage, the surgery apparently added nerve damage (retention and incontinence, maybe more ED complications). Before surgery herbal or prescribed meds., but diminishing in effect over time.
I saw a Urologist after surgeries and we started with Injections but my big problem is venous leakage, so it wouldn't maintain long enough to finish. I'd need a ring, at least. (ouch, ouch, ouchouchouch), The prescribed pump would get me to a great start, but again, rings are needed to maintain when the pump is removed; too much pain to proceed with coitus.
Huge next step recently was to have an implant. After 45 days, it's gone from a lot of constant pain to tolerable pain occasionally. Doctor cleared me to start using the pump last week; it causes intense pain, effectively useless for now. First few attempts were excruciating (imagine your erection crushed flat in a vice) - but that supposed to go away with more use. Doctor recommended pumping up 1X a day until then and eventually reducing it to at least once a week.
I'm going to go through the unavoidable pain (or no gain) until it proves itself, or six months. It's not usable for ANY purpose yet; no pleasurable sensation is possible with such pain. I intend to find it usable in time. I'd like to hear from others who've stuck it out as to their difficulties and eventual results with implant surgery.
So I sympathize with your situation and advise seeing a urologist; go through the testing and steps toward a solution. Definitely try the ring first, with herbs or meds, before getting a pump. Rings are available cheaply and discretely through any adult store or on line. If you can't take the pain of the ring, then don't waste your time with a vacuum pump. Shots aren't painful. I've used Testosterone in several forms before finding injections work best for me; least hassle.
Good luck!