Penis tip irritation lasting weeks, happens within 24 hrs of ejac

[Darty17]

34 M. Swelling and irritation of meatus/urethra opening within a day after sex or masturbation. Has happened 6-7 times since beginning of 2017. Only known changes at that time was switching from Cymbalta to Viibryd and a new partner (has tested clean for STDs). Can feel better in 2-3 weeks with meds (cipro with and without diflucan) or without meds, but ejaculating during this makes it last longer (had sex and masturbated twice during current "flare", going on 7 weeks of length). Occasional minor discomfort after urinating, especially when it is more concentrated. No discharge or itching. Dull ache and occasional sharper pain when touched around the opening, around the backside of head, and sometimes a bit down the shaft. Also have slight red rash on upper head/glans - not itchy, not scaly, no bumps - just there.

Urine and blood tested neg for chlamydia, gonorrhea, syphilis, trich, hep c, HIV, and e coli. Cystoscopy in November found nothing except a soft stricture 16 FR in proximal urethra. CT in November found nothing (except a 19mm kidney stone. Two procedures to get rid of that). DRE in November found nothing off about prostate.

PCP thought urethritis (but no discharge or pain when urinating), yeast (not itching, on a no-sugar diet, meds did nothing), so out of ideas. Urologist out of ideas, except to use more lube (using same as I have my whole life, though this did start after being with a new partner for a couple months). Dermatologist said contact dermatitis, gave me hydrocortisone 2.5. Didn't help. Gave Eucrisa. Didn't help. All specialists basically said that they could not see anything physically wrong.

Went to ER 4 weeks ago with "epidydimitis" - swelling, discomfort, and some shooting pain in upper right groin area and right testicle. Ultrasound of testicles was fine. Doxy for this seemed to help.

Also noticing more urine dribbling after every time I pee. Stop peeing, but get 4-6 drops worth within a couple minutes after finished.

Have used: Cipro twice, diflucan 3x, nystatin cream for balanitis, nystatin oral, uribel, azithromycin, moxifloxacin.

Sorry for the length, but wanted to give full picture. Does this sound like I am now more sensitive to damage there, so I do need more lube and gentler intercourse (Not that I am super rough), or are there other things that should be investigated? I am open to ideas for diagnosis, ideas for specialists to see, ideas for tests to be done, ideas for lifestyle changes, etc. Basically, I just need your help.