What is the difference between whining and complaining?

I´ll let Rarity explain...

Why, I can't put much thought on complaining, but would Ты like to hear whining?

THIIIISSSSS IS WHINING! THIS упряжь, ремень безопасности IS TOO TIGHT! IT'S OUT OF SHAPE! Can't Ты loosen it--AND OH! IT HURTS AND IT'S SOOO RUSTYYYYYY!

*Proceeds to babble on about the filth of the упряжь, ремень безопасности and other bits & bobs about the тележка, корзина and being the 'mule' to pull it*

There~ Now, where is dear Opal?

If Ты complain, Ты have the option of nor whining.
If Ты whine about something, it is almost always a complaint.
Why do Ты ask?

rarity please help me

Whining is when Ты cry really loud and your voice gets pretty high pitched.And complaining is when Ты tell someone about the thing that you're disliking.And Ты don't have to be too loud.
And whining and complaining have something in common.They both mean to be upset about something Ты don't like.