Yes! Sounds like sensory issues, and you're doing a great job asking for help now.
My daughter was similar in some ways, but I didn't know what sensory issues were then. Pediatricians were useless, because this type of thing is not bad if you're only with the child 5 minutes, but if this is your world 24/7 you need HELP! I've been there.
The good news is that at age 8, while we're still dealing with dyslexia and periodic anxiety, the sensory issues are gone.
Try cranio-sacral massage therapy. The first massage decreased my daughter's sensory issues dramatically. She slept all night and woke up happy for the first time in her whole life the night after that massage. WOW! It doesn't work like that for everyone, but you'll know if it's really helpful for your child after the first massage. She was 5 1/2 then, and I was so sad I didn't know about this sooner. We started at Sally Fryer's clinic, Integrative Pediatric Therapy for an evaluation, and now use www.kenpiercy.com for cranio-sacral massage. We did 18 months of OT, but our insurance wouldn't pay for IPT, so we went elsewhere. ECI might do OT for free.
Chiropractic care might really help too. I wouldn't have guessed this, but it has helped me and all 3 of my kids feel so much better since we started going. We see Melissa Shelton at Preston and Hedgecoxe. Her practice is about 30% kids, and she's very gentle. Insurance will probably cover this too.
We do all natural diet, get lots of excercise, play outside as much as possible, look for sandboxes, swings and have a trampoline at home. We avoid structured activities, and I do not hesitate to leave a place if behavior deteriorates. My daughter used to lay on a desk chair and ask us to spin her (age 2), or spin herself standing up. We asked her once why, and she said, "it helps me grow."
We got her a 10 pound blanket to sleep under starting when she was about 5 1/2. She said it helped her fall asleep better. Ask an Occupational Therapist if this might help your son. Sometimes the OTs have "loaner" blankets for you to try at home.
Another helpful book is "Raising Your Spirited Child." Patience, consistency and battle-picking are survival skills in your world.
Pursue the food sensitivity investigation - it may be causing more trouble than you realize.
On the bright side, you may have a track star there.
Hang in there, and keep looking for other moms who have this kind of high-maintenance kid. Particularly when it's your first, you have no basis for comparison, so it's really easy to feel like you're not measuring up somehow as a mother. In reality, you have a different challenge than most moms. Half the benefit of those therapies is sitting in the waiting room with other moms whose kids are similarly challenging and swapping stories and ideas of what to try next.
Good luck,
S.
SAHM of 3 (8, 6 and 2)