Try describing the pain using the OPQRST pneumonic.

Onset - what where you doing when it started?
Provocation - does anything make it better or worse
Quality - what type of pain is it. Stabbing, burning, etc.
Radiating - is the pain in one spot, or does it radiate out to other spots.
Severity - what's the 0-10 pain scale.
Time - How long has this been occuring

https://en.wikipedia.org/wiki/OPQRST

As you can see, Severity is just one of the parts of the assessment.