Your toddler's negativism – saying 'no' all the time, running away, throwing things – has probably been surging lately. He's actively testing his limits, putting his new-found mobility and ability to control his environment to use.
It's your job to create and enforce those limits. Your toddler's negativism will affect feeding, sleeping, playing – basically, every area of significant interaction between the two of you.
They're common in toddlers, along with other types of openly negative, provocative behaviour. Remember, this is all a normal part of his growing independence, not a plot to drive you crazy!