Partial Erection problem

[Matty25]

I am 25 years old and in good physical health. In the past 5 months, anytime I get an erection, it is not at full strength but maybe 70%. As it comes, it starts out okay but in less than a minutes time it starts to fade. When I am on my back is when it is the most difficult to maintain it. In trying to keep it up, I will contract my muscles in the pelvic region and it feels like it gives it a little more power.

Question 1)
Is this damaging to those muscles and to the vascular system, and does it cause venous leak?

I had visited a specialist in Erectile Disfunction about 4 months ago and they conducted a doppler ultrasound after running a low dose of prostaglandin. They said that the blood flow was normal and ruled the condition as phsycological ED.

Question 2)
Wouldn't a doppler ultra sound detect a venous leak?

They suggested I order a supply of Prostaglandin to use before sex to boost my confidence and then I would no longer need it.
However I could not afford it, so they suggested Cialis-It did not work. I had heard that testosterone could play a part in ED so I had it checked and found it to be a normal high. I then consulted a Urologist and he has scheduled me for another doppler in spite of the fact that I took one 4 months ago and he says he is 90% sure it is venous leak, and that there is only a 10% chance that it would be phsycological. He also said that if I was not fully erect after a low dose of prostaglandin then something physical was to blame, not phsycological.

Question 3)
If this is a venous leak, what can be done to fix it?