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......