What Causes Swelling Around The Testicles?

I am 19 years of age and at the beginning of the year i had a minor cough/sore throat. During the illness i began to feel an awkward feeling in my left groin which then developed into swelling my left testicle. I booked an appointment with the GP and within minutes the doctor said it was a Inguinal Hernia which he concluded through touching the area and asking me to cough a couple of times. He told me to just stay away from the gym or lifting heavy objects as it hadnt of developed into a lump and was fairly small (assuming it would go away after time). 2 weeks passed and i began to worry as i still felt swelling around the testicle area and tend to normally worry when it comes to that region. So i went to a walk in centre and the doctor said the exact same thing, it was a hernia and concluded this with the exact same method the previous doctor used, however this time he told me to make an appointment with the GP again and ask for surgery to be done if i want it to be fixed although it is very minor and probably wont need surgery. Now this is where i get suspicious and worried, i booked the most recent GP appointment and the doctor completed the same method the previous doctors had done, however he said he couldnt spot anything and that i didnt have a hernia, however i still feel swelling around that area mainly when im sitting down as my day to day job consists of working in an office. I check my testicles regularly and there are no lumps, just a sensitive feeling when i touch the side of the testicle where the cord is attached.

I have a scan in 3 weeks however i am worrying at this moment in time as i dont want it to be anything serious. The most recent GP who booked me in for a scan says that he doubts they will find anything in the scan, however i just want to calm my nerves.

Thanks