Can an sti cause a tight scrotum when standing or active. my scrotum is only loose when lying or sitting. im in my 40s and its only been like this for 6 months??

What you describe is not a known symptom of STI. If you are bothered by that feeling, please see a urologist. Good luck.

sexually transmitted diseases do not affect the tone of the muscle in the skin of the scrotum- which is responsible for its looseness or tightness. That is affected by the temperature Hot -loose cold- tight and also by other things like area stimulation etc. What you feel is not abnormal.