how do i retrieve my fitness history

joygan,

If your storage is full and you are unable to back up, you would need to free up some storage first:

"Make more space available in iCloud

If you run out of iCloud storage, your device won’t back up to iCloud, new photos and videos won't upload to iCloud Photos, and iCloud Drive and other iCloud apps won't stay up to date across your devices. And you also won't be able to send or receive emails with your iCloud email address.

You can free up storage in iCloud by deleting content that you're not using:

• Check Recommended for You
• Reduce the size of your iCloud Backup
• Delete photos in iCloud Photos
• Delete folders or files in iCloud Drive
• Delete texts and attachments in Messages
• Delete messages and manage Mail
• Delete voice memos

Before you delete anything, you might want to archive or make copies of the information that you store in iCloud."

Additional details can be found here: Manage your iCloud storage

Another option would be to back up and restore using a computer.

Cheers!

Hi joygan,

Thank you for participating in the Apple Support Communities. We understand your health and fitness data didn't fully transfer from your previous phone. It should transfer when you sign in with your Apple ID if you're using iCloud. If you're not using iCloud, you'll need to use an encrypted backup on a computer. This article explains more: Back up your Health data in iCloud on iPhone.

"If you sign in with your Apple ID, your health and fitness information in the Health app is stored automatically in iCloud. Your information is encrypted as it goes between iCloud and your device and while it’s stored in iCloud.

In addition to using iCloud, or if you aren’t using iCloud, you can back up your Health data by encrypting a computer backup. See Back up iPhone.

Note: In order for your Health app data to sync across devices, make sure your devices are signed in with the same Apple ID, are connected to the internet, and are updated to the latest OS version.

Manage your Health data in iCloud

You can make sure your Health data is synced across all of your devices. You can also stop storing your data at any time.

1. Go to Settings  > [your name] > iCloud.
2. Tap Show All, tap Health, then turn Sync with iPhone on or off."

Take care.