Toddler Side Pains

My son is 27 months old and this week has been rough for him. He started out with a small cold and then he started complaining about "booboos" on his right side around the low of his rib . Then started pointing to his chest saying " mama bobos" and crying and whining. Then he became extremely exhausted, lethargic, wanting to go to bed early, sometimes he won't sleep all the way through the night.
\Today he hasn't eaten much but has the runs and then puked all over my couch and then he (for the first time) asked to go for a nap and when I asked if he wanted to lay in my bed he refused and wanted his own (totally not like him)
I'm really worried about the side pain he's complaining about but I also don't know how reliable it is coming from a two year old..could it just be for attention? I kind of want to bring him to the hospital ...but not sure if I should  

I would bring him in to be seen

I would definitely bring him in.

Take him in and tell them about the side pains he is complaining of. I'd be worried that it's something more... but it could just be aches and pains from being sick.

Well the biggest reason I'm worried is because my sister (mind you she was 13 when it was discovered) has complete kidney failure.. and shes had them since birth just never was caught until she almost died from it.
I am having a nurse come look at him before I decide to bring him , thank you!

I hope he is okay!