Thanks for the query
From what it looks, it looks like a benign lipoma
on the screen added to that u have told it is soft in consistency. The only point against it is that it doesnt resolve on its own.
The next d/d is a hematoma
. PLease take a FNAC of it this time before it disappears to know the root cause of the problem
I am so happy u took a picture and uploaded. It made things easier
Have a healthy life