Yes , Keeping the legs crossed one over the other for longer periods ( more than 5 min)does decrease the blood circulation in the lower half of the legs and can cause pain in the muscles. There are no long term studies done on this topic that says that this habit can lead to either of the conditions you have mentioned.

Sitting with your legs crossed may not always be bad; it’s the sitting in the same position for hours on end that can be. Fight a sedentary lifestyle by getting up to take walks every half hour, stretching, and focusing on sitting up straight. It won't cause varicose veins but it can cause a varicose vein to further worsen,

Dear patient Your given history is inconclusive so some more information related to your problem are required for better advice For a disease to cause many factors may be associated so requires proper evaluations

Hi. Crossing legs for longer durations is not advised.