Is it varicose veins?

I have had blue veins protruding slightly behind my knees for a long time, and when I walk a lot or wear shoes, the back of my knees feels heavy and painful, and my legs tend to swell. But recently, when I walk a lot, I often feel a heavy and painful sensation from the back of my thighs down to my calves. It also feels like a pulling sensation. The blue veins initially were about the size of a 500-won coin, but now they are spreading a bit more widely. Also, is the pulling sensation at the back of my thighs caused by varicose veins? If so, I am curious about the treatment methods or exercises. I’ve heard some scary stories saying that surgery is always necessary.