What can you tell me about vericose veins? What is the cause and can they be painful?

I have noticed over the past couple of years that I am starting to get vericose veins more so on one leg than the other. The jobs that I have had over the past 20 years have required me to be on my feet throughout most of my scheduled shifts.

I am curious to know if there is pain associated with vericose veins. I notice that one of the most prominent viens that I have on my right leg tends to be painful when it starts to protrude. I notice this most often when I workout.

I also notice that when I workout(lifecycle, bike, treadmill) sometimes my right foot starts to go numb. I get a tingling sensation in the foot that feels like pins and needles. Not sure if they are related.

Any suggestions?