I'm not seeing things so well vs I was coughing last night

[Guzhao67]

Dear professor: could you please tell me the difference between the following two sentences in terms of the ING form?
1. I need some spectacles. I'm not seeing things so well these days.
2. I was coughing last night.
what's the semantic function of ING form here? emphasis or whatever? and why?
thank you very much

[Mister Micawber]

1-- Stresses duration, hence highlights the disability
2-- Stresses duration, hence highlights the disability.
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Native English teacher at Mister Micawber's