Symptoms: * no desire for sex * difficulty "getting it up" * burning pain and tightness down back of legs/inside thigh (above knees) * lower back pain which comes and goes * severe shooting/stabbing pain rectal pain, lasts seconds then dissipates * painful knees and ankles, seem worse in morning after waking (feels like day after a long run) * lightheadedness at times * sometimes an urgent need to pee/sometimes stop-start peeing and feeling of not being fully void * testicular shrinkage/mild discomfort * twitching nerves/muscles legs, lower back and sometimes arms/shoulder, worse when lying flat at night? All have persisted for weeks now and on occasion I have had a really swollen lymph nodes under left arm. no blood in stool or urine, and otherwise healthy at 30. BMI is good, blood pressure is good and blood sugar is all good. Telephone call with doc where he suggested it could be sciatic pain but i think that rather unlikely given the above symptoms. Had bloods taken Friday and awaiting results, urine swab test showed nothing of concern so sample not going away for any further checks. any help welcome, it is starting to get very depressing. thanks
You seem to have both urological and neurological symptoms. Get a referral for both specialists and show both your list of symptoms. These issues are above the pay grade of a family doctor.
Did you get your results? It might be prostatitis because of the symptoms.
Have you been taking any natural ingredients that might calm down the situation?
I had similar situation, got so frustrated and tried everything, eventually I changed my lifestyle and started taking some natural ingredients via. supplements. I can say it is getting better now 
sounds like you have a hypertonic pelvic floor. i have somewhat similar symptoms. frequent urination, muscle spasms here and there, tightness everywhere. have you seen a pelvic floor physical therapist? had ED for about a week but it subsided thankfully