Grammar, Usage / Help with Comma Usage and ING verbs [4]

Which is correct -
1) She reports significant pain at night, limiting her ability to get a full night's sleep.
OR
2) She reports significant pain at night limiting her ability to get a full night's sleep.
Another example:
1) He has extensive pain in the lower lumbar area, radiating down his legs.
OR
2) He has extensive pain in the lower lumbar area radiating down his legs
And why is it correct? Please provide the grammar rule if you can.
What is confusing me - "Limiting/radiating" is the second verb in the sentence, first verb being "reports/has." The pain is actually what is limiting the ability to sleep/radiating down the legs, so it that an adjective phrase describing the pain that should be set apart by a comma or am I splicing the verb (limiting/radiating) from the subject (pain) by adding a comma?

This is driving me crazy and I can't find a rule that seems to pertain exactly to this situation. Thank you!