Using Filter and Query context together

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Describe the issue:

I am trying to search a set of words and also filter the results using filter and terms options, however, the query does not return anything. If I remove the filter and terms options, then it returns results.
Need help in understanding why this happens.
Here is the query I am using -
search_query = {
“query”: {
“bool”: {
“must”: {
“simple_query_string”: {
“query”: “Heart”,
“fields”: [‘section’, ‘subsection’, ‘question’, ‘answer’],
“default_operator”:“OR”

                    }
                },
                "filter": [
                    {
                        "term": {"section": "Medicine"}
                    }

                 ]
            }
        }
    }

Configuration:

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