OCD- Trash obsession

Hello,
I have a 3 year old boy with speech delays and a sensory processing disorder (craves heavy work).  Recently he has become what I feel is obsessed with trash.  Ex. Has to have cans and recycling bin at the curb all week.  Wants to always take trash out.  When at the playground will spend 90% of the time picking up trash and putting it away.  We need to look in all dumpsters when coming and going from preschool, stores etc.  He runs away from me to see the trash in the cans.  When I say no we need to go inside he has what I call episodes.  Horrible screaming and falling on the ground which will last 10-15 minutes.  Some days he has 4-5 episodes.  
My question is does this sound like an OCD related thing or an autism thing?  I need a starting point and I really don't know who to ask first.  OT or Ped.  Any insite would be extremely helpful!  Thank you so much!

[ashebs]

sounds like both/ either because autism has repetitiveness and temper tantrums and ocd has repetitiveness as well id ask ped about both as possibilities.