Well about a month 1/2 I got a new sofa microfiber its red and black an ever since myself and kids got a terrible itchiness on our back, legs and arm. I don't think it has any type of little animals. There new what could it be??

You could be having a reaction to chemicals that have been used to clean it or sizing (keeps the fabric stiff while being cut and sewn) left in the material from manufacturing.

If it is new, you might contact the store where you bought it and see if they know of any complaints about other pieces from the same manufacturer or if they might have used something on it.

Do you have the ability to get it cleaned? If not, try putting a cover/sheet over it and see if you still get a reaction.