Discharge causing unbareadle itchy and little swollen on tip of penis

Im 20 ys old and from the past 5 days i m having a discharge grey in colour causing itchy and a little swollen to my penis on the upper skin part. After wasing away the discharge the itchy sensation goes off... so in a day arround three times it will happen like that. And on the inner part of my penis is causes a small spot looking like a bubble... im too much worried about this... I have a thinking that this might be caused by having sex as i used to have arround 3-4 time every week but now i cant even do it the swelling part used to get pain a lot... this swelling is on the tip portion of the skin only.... plz help me out what to do...