That does sound like varicose veins. Often these are harmless and you can self treat but do show them to your doctor on your next visit. Prop your legs up and elevate them, you could try regular exercise which helps (if you are cleared for activity), losing some weight if you need to and compression stockings can help keep them from getting worse. If they do get worse or they really worry you, then see your doctor now about them. There are good treatments these days. https://www.mayoclinic.org/diseases-conditions/varicose-veins/symptoms-causes/syc-20350643
Blood clot is the main worry and if you have consistent swelling or pain, get checked right away.
Hope this helps.
Hello~If you haven't already done so, I would make an appointment to see your GP, it may not be serious, but then again, it could be a circulation issue that needs to be taken care of. The fact that having pain when you walk concerns me as it could be some blockages in these areas called "Intermittent Claudication"