I do not see an obvious cause for the pain that you experienced with your orgasm . I have not seen this symptom related to kidney or ureteral stones. That being said, your frequency and urgency as well as one sided scrotal pain are definitely symptoms of a kidney stone in the ureter.
Pain and anxiety are two of the many thing that can cause loss of libido and sexual dysfunction. It is often difficult to sort it all out for a given patient.
Your back pain may well be just that, pain in the back of a muscle/joint cause. A pinched nerve can give back pain, genital pain and leg pain as well as affect sexual ability. The onset of your pain may well be a pulled muscle related to your skateboarding. I think that your back pain could have it’s origin here also. However, I am very much guessing.
You are making good efforts to take care of yourself and next time that you see your physician, do suggest a tie-in between all of this. In the meantime, try some warm baths and motrin (around the clock, not just with pain) if you do not have any contraindications.
i have nearly the EXACT same symptoms. lower back pain, minor pain while ejaculating, difficulty achieving orgasm. i can become erect easily but the head is not filling with blood quite as large as normal and that is affecting my pleasure. i feel like my penis is going numb the longer i have sex, the sensation decreases dramatically after 10 minutes. i have some pain in the testicles during and after sex. I broke my back 3 years ago and could have nerve damage but why has sex been excellent up until this point? i am mid 20's and shouldnt be experiencing erectile dysfunction. after ejaculation i get minor itches or a pins and needles type feeling inside my urethra. i did have chlamydia a few weeks ago but was tested and treated, could i maybe still have it? my girlfriend and i waited 5 days before resuming sexual activity as recomended.