Why do I have such anxiety when my phone isn’t on me, which prompts me to periodically tap my pocket to check on it?

A few key properties of phones:

• Will cause significant pain and expense, in both time and money if lost
• Small
• Carried around everywhere

Beyond keys and wallets, there are not many other objects that can inflict so much pain & expense on one’s life if lost, while simultaneously being small and carried everywhere, which increases the chance of losing it. Thus producing a natural reaction to check if it’s there, and anxiety if not found. And furthermore, unlike keys and wallets, phones actively provide dopamine.