I contracted chlamydia, treated. one day after masturbation big glob of yellow mucus comes out and my underside of my penis was burning. tested negativ?

STD: I think you must be evalauted by a urologist or family doctor. Did you confirm the chlamydia is gone? Was your partner treated? Did you get tested for other sexually transmitted diseases?

Possible gonorrhea: Yellow thickened discharge from the urethra with discomfort is often associated with gonorrhea. Chlamydia is often a clearish discharge with present. Seek medical evaluation for testing appropriate treatment.