I was asked such a question: "How to detect the difference between the meanings of "I've changed a lot (myself)" and "I've changed a lot (in my life)" if we see this statement without any context or any further explanation?". I was puzzled...
The first could refer to internal changes (character, etc) and the second to external (work, family, etc). The first could also mean (if the word 'myself' is included) that you made the changes without assistance. Without further context, it is difficult.