Show related entries without current entry
You're wanting to show a paginated list of related entries from a single entry page based on a tag relationship, correct?

This should point you in the right direction:

{% set segment = craft.request.lastSegment %}

{% for entry in craft.entries.slug(segment) %}

    {% set tagId = entry.myTagFieldHandle.first() %}

    {% set relatedEntries = craft.entries.relatedTo(tagId).id('not ' ~ entry.id) %}

    {% paginate relatedEntries as related %}

        {% for entry in related %}

            {{ entry.title }}

        {% endfor %}

    {% endpaginate %}

{% endfor %}