So glad Jake is fine.  I have a similar issue.  I have an old blind traumatised bulgarian former chain dog, Denzel.  He lives in my kitchen and utility room.  I can touch him but he bites anyone else and you can't lift him etc.  He has a quality of life after 8 months but it's about him being relaxed, warm, fed, spoken to and chilled.
About 6 times he has yowled after feeding for about an hour.  I am hoping it's indigestion (he gets a little constipated) but the idea of getting Denzel to a vet is horrific and would traumatise him.  
The journey was bulgaria left him in the corner of my kitchen pooing and weeing where he sat shaking for over a week.
He trusts me on his own terms.  
I live in fear that the yowling is because his teeth are sore and he needs a vet......