I picked at a preexisting mole on my shoulder, and now it is inflamed and darker, and the skin around it is red. is this something to be concerned about? or was it probably just from picking at it. also, it didnt itch or hurt before?

I'm sure you realize it's not advisable to pick at any skin lesion. It does appear that you caused irritation/inflammation to occur. Observe for spreading redness which would indicate infection. Otherwise when all the irritation subsides, if your skin doesn't look perfectly normal or level at the site of the original lesion, have a physician or dermatologist examine and advise you.