Prickling sensation in feet while near electric cables - should I worry about this?
You would need to define "near" and consider the surface you are standing on. The issue is that many devices that use what are called "Switch Mode Power Supplies" (SMPS) can produce what is called Common Mode Noise, a type of electrical interference that is referenced to ground (earth). In a good quality product, this is taken care of with proper grounding and shielding of conductors and / or filtering. it could be however that you have a combination of issues taking place and something is NOT properly taking that noise to ground, so it is "leaking" all over the place. Then combine that with dust, dirt and or moisture in the environment collecting on your cables, and a slightly conductive floor material, it is entirely possible that you might be able to perceive it as that "tingle", akin to feeling the "zap" from static build-up when you walk across certain floors. 

The first thing I would be concerned about with this is that the grounding for your equipment in failing / broken / missing. That can have other serious consequences.