Music Authorization for Device

Hi,

I am finding more and more music in my collection that is getting "not authorized" to play on this device. At first, it was a random song here or there, but its turning into a larger problem and i'm discovering more and more.

I have read numerous support articles and have read numbers other publications, but nothing is seeming to work. Things I've checked and validated and challenges:

1.) My purchase history of music with Apple goes back years and years and years

2.) Purchases could have been made on any of 10 different iPhones, multiple iPads, or a number of different Macs.

3.) I only have or have ever created 1 apple ID, it goes back to the @mac days and has remained unchanged, other than password changes

4.) I only have 3 devices currently authorized (2 macs and 1 phone) to play music and my master library is on my mac (not a phone, not an iPad)

5.) I've logged out of iTunes (music) and logged back in, my current devices are all authorized correctly under my 1 apple ID

6.) All of my software on my phone and my macs is current--thats not the issue.

Questions:

1.) How do i even determine my master list of music that is not authorized or having errors? I stumble across songs all the time, but how do I completely validate what is and isn't working or showing authorization problems based on purchases? I have tens of thousands of songs in my library, I can't go through each one individually.

2.) Purchase history when I look at it through my account is last 6 months to a year--not sure, but how do I download a complete music history purchase?

3.) What is the real solution to this problem?

Would appreciate some clear guidance on this, as I'm not even sure how I go about determining all the problems that I have with my music