Is It Right Usage?

[lenanils]

is it right usage saying " I'm going to walk or I went for a walk"

[sandyRoe]

Going to, future tense. I'm going to walk to work tomorrow. Went, past tense. I went for a walk yesterday.
Both OK.

[shoota]

Both could be correct depending on what it is you want to say...

[Milvus]

Both are correct in the right context.
How are you getting to the station? I'm going to walk.
What did you do after lunch? I went for a walk

[Obiter]

But if you are just going for a stroll without any particular destination in mind you would say, "I'm going for a walk".

[Svejk]

it depends. To walk suggests the method of getting somewhere as opposed to a walk which is an activity in its own right.