Both of these do not make sense, the correct form should be as below:

I have been learning English for 2 years. OR I have been learning English since 2015. (OR since high school etc.)

If you want to use "ago" you can say:

I started learning English 2 years ago.

He started living here 20 years ago.

Since gives the starting point of actions, events or states. It refers to when things began.

Since + a point in time (in the past), until now. When you add "ago" after the time it doesn't follow the meaning to "until now" instead changes the meaning to a point in time before the stated event, therefore is not grammatically correct to use ago with since.

 Examples: I've been waiting since 7 o'clock.

I have known him since January.

For + a period of time 

To measure a period of time up to the present, we use the present perfect tense and not the present tense.

I have known her for a long time. (Correct) 

I know her for a long time. (Incorrect)

I have lived here for ten years. (Correct)

I live here for ten years. (Incorrect)