Yes, he's 3 now. Yes, it is a growth spurt.
Yes, at EACH age juncture or on the cusp of an age change... it can really tweak a child.
No, the "emotions" of a child, is not even fully developed yet.. nor understood by them completely yet, nor are they "able" to master their emotions NOR how to cope with it.
So, they need us, to help them. Help him by teaching him the "names" for feelings and how to tell you how he feels. Thus, he will learn how to communicate and express himself well, as he gets older. Building articulation about himself and self-awareness.
Yes, they do still need naps at this age. Even Kindergarten kids nap. It also helps their brain development and moods.
Yes, a "growth-spurt" ALSO means changes in: motor-skills, cognition, emotions AND their physical growth.
So they have MANY things on their plate now... that is affecting them and that they are adjusting to. So, at times when they are having trouble wallowing through it... they have us, to help them.
When my son is like that... I don't scold/punish him for it... for growth changes or misunderstandings or when i know he is TRYING to handle something himself but is frustrated. But I tell him he is learning, he is changing and I will help him... but for him to tell me how he feels... and Mommy will help. But we are family and we talk nicely... to try his best. BUT... its okay to feel "grumpy" sometimes because adults do, too. So, I tell him "we are a team..." and he likes that... then he feels he isn't the only one... kind of thing.
3 is a harder age than 2.
Him having 2 tantrums over the week... is not much!
The book series: "Your 3 Year Old" is also great. Its about each age juncture and what THEY go through. Its a quick read. Although written years ago.... it is still pertinent and enlightening. They have a book for each age set. You can get it from www.amazon.com
And yes, when he has his check-up, ask the Doctor about his "pains" unless you take him in earlier, just to rule out illness.
All the best,
Susan