What Causes Itching Around The Neck, Shoulders And Underarm?

In the past 1 1/2 weeks I started to itch only around my neck, shoulders and under arm areas, but since then my whole back itches, sometimes my arms, hands and various places on my legs and feet. It is very annoying and keeps me awake alot. I did add a Probiotic about one months ago called Culturelle and have had 2 RX for Antiobiotics for some plastic surgery I had 9 weeks ago, but pretty much everything else has stayed the same except my STRESS level had been through the roof trying to find and making the decision to move my mother out of my home and into a Residential facility community. HELP!!! would love to sleep normally without itching all the time. Thanks