Is there any such thing as back tendinitis?

I've had a sore back before and used to go to the chiro monthly, but this is different. It hurts in a V shape with the point at my sacrum and the side going up to the crest of my hip. It seems to follow the attachments of the various spinae erector muscles.

It's not terribly painful, but there's weakness that keeps me from maintaining lumbar extension in the hole when squatting with my working weight.

I was planning to work out with light weights when squatting and dead-lifting until it calms down.

Any comments or advice is appreciated.

Matt