Autism and social skills

Hi, I am new to this forum and am looking for some advice!

My little boy who is now 7 has been assessed for ASD but was given a no diagnosis due to improvement since his younger years however has been said to have traits of ASD and pends further investigations if they persist.  

My question is about the traits he shows specifically within the social aspect and wondered whether anyone else has seen this with their children, whether they have an ASD diagnosis or not. 

When my son plays with other children, he automatically assumes that when he approaches other kids, that they know what game he is playing.  For example, he was at martial arts today, 2 boys were playing tag together and my son ran up and started to play along without telling them he wanted to join in, so the boys were non the wiser that my son wanted to play, however my son firmly believed that they were aware he was now apart of the game. (I hope I am making sense).  

Another thing I have noticed is how bothered he becomes when children don't want to play a game with him, he can play the same game over and over and over again so it can be quite repetitive and can become quite upset if they don't want to play anymore but is quite happy to tell another child he doesn't want to play a game with them if he isn't up to it what not.  

I wondered if this is similar to anyone else's children?  It's quite upsetting to watch sometimes when I see him with other children at times.  

thanks :)