Thanks for the clarification,
It is likely a hemorrhoid then. They have a purplish appearance. I will add a wikipedia link that has a picture of a hemorrhoid at the end of this answer so you can compare what you are seeing with the picture.
Hemorrhoids typically develop for several reasons: pregnancy/childbirth, diarrhea, constipation and straining, prolonged sitting.
They can bleed, so if you see bright red blood on the toilet paper after wiping, do not be alarmed.
Hemorrhoids can become thrombosed, meaning a blood clot develops in them. This can make them extremely painful. I do not think you have this as your pain is not severe.
In order to treat hemorrhoids, you want to ensure soft stools by drinking plenty of fluids, adding more fiber to your diet (bran and possibly a fiber supplement such as citrucel or benefiber), avoid straining and sitting on the toilet for long periods. You can also buy over the counter hemorrhoid creams and a sitz bath.
Here is more information (much of this I already covered):
Here is the link to a picture
If this does not look like what you have or if you have more questions, please let me know and we can discuss more.
I hope this is helpful for you,