Circle times and standing in lines are difficult for my son, who has SPD. Increasing the physical distance between themselves and others is their way of avoiding unexpected touch.
What may need to be discerned is whether its a social problem related to skills or a social problem as an outcome of sensory, particularly tactile, defensiveness and overload. Social skills classes may help with the former and OT with the latter or you may need both.
SPD can be a stand-alone or co-morbid with ASD. You'll see overlap of some symptoms.
I've provided a link to a checklist below, but the only way to know for sure is to schedule an appointment with an OT. Please note the checklist includes traits of Sensory Avoiders as well as Sensory Seekers.
For further reading: "Sensational Kids" Lucy Jane Miller & "The Out-of-Sync Child" C. Kranowitz. My favorite is Miller's.
Good luck!
http://www.sensorysmartparent.com/sensory-checklist.pdf
