PLEASE HELP! Tip of penis red and meatus is inflamed!

hello everyone. My tip of my penis has been inflammed and is pretty red. My urethra looks the most red and theres a bump on the urethra. Theres been like a burning sensation followed by some shooting pains every now and then. that lasted for THREE MONTHS. i thought it was getting better but looks to be worsening. i have been tested for the average std like chalumydia, gon, hiv/aids, syphilis, all that was negative. Please give me
some insight! i would greatly appreciate it.