Q: Apple Watch problems after IOS 8.4 Upgrade

Hi Patrice

Have you tried to force restart (different than just restarting) both your iPhone and Apple Watch?

Force restart Apple Watch: press and hold both the side button and Digital Crown for at least 10 seconds, until you see the Apple logo.

Restart your Apple Watch - Apple Support

Force restart iPhone: press and hold both the Sleep/Wake and Home button for at least 10 seconds, until you see the Apple logo.

Restart your iPhone, iPad, or iPod touch - Apple Support

Then try pairing again, ensuring that:

- Your iPhone has Bluetooth turned on (Settings > Bluetooth)

- Your iPhone is connected to Wi-Fi or a cellular network

- Your Apple Watch is turned on

- Both devices are charged and you keep them close together as you sync them

Set up your Apple Watch - Apple Support

Have you also tried to pair your Apple Watch and iPhone manually?

Put on Apple Watch, choose a language, tap on "Start Pairing" on both devices, then follow these steps:

• Tap "Pair Apple Watch Manually" on your iPhone.
• Tap the info icon (a large letter i) on your Apple Watch. Your device's name should show up on the watch face.
• On your iPhone, tap the device name matching that shown on your Apple Watch display.
• A six-digit code will appear on your Apple Watch. Enter that code on your iPhone to pair the two devices.
• Then continue the normal set up steps (but choosing to restore from the Apple Watch backup on your iPhone when given the option). 

In that case, I can only suggest that you contact Apple Support:

https://www.apple.com/support/watch/contact/

I am having the same problem!