When attempting to do a heart opening meditation or any guided meditation that focuses on the heart chakra...I feel numb. I feel no sensations, no warmth...no glowing light...nothing. There is a sense of a big void there...a black whole...is the best way to describe the "nothingness" I feel.
The heart center is the key to spiritual awakening and you are right to want to access its power, vitality, and natural love. I assume that what describe is also the case day-to-day and not just in meditation? Would you perhaps describe yourself as more focused in your thoughts? In the mind? Do you enjoy music? Not just rock or pop music, but also some beautiful and uplifting music? Do you enjoy chanting? Do you appreciate beautiful art, or nature? Is there someone in your life towards whom you feel pure love?
Why am I asking? Because I would encourage you to use whatever aspect of life inspires and uplifts you to build a bridge towards God or guru, or towards unconditional Love itself. Maybe there’s someone, past or present, whom you consider to be a true hero!
Paramhansa Yogananda once counseled to the effect that if one doesn’t feel devotion then “Pray to God for devotion.” Consider those things or people that you DO feel deeply towards; “meditate” on that person for a few minutes; focus on the feeling of love, respect or admiration that you feel towards him or her; then, “extract” that feeling, separating the feeling from the person and meditate on that feeling. As it remains with you for a few minutes lift that feeling upward to the spiritual eye and offer it to God and guru. Do this with every meditation.
As a subsidiary suggestion and a supportive practice, work on long, slow and deep breathing as part of your meditation. Inhale (as if right into the heart), hold the breath, and pull the shoulder blades back, while holding that position, focus on the heart center; then, exhale as if right back out through the heart. Sit briefly with break held out and quiet, remaining focused in the region of the heart (the center, not the physical heart). Imagine your are going into deeper and deeper levels of the heart center, down past emotions and blocks into the giant wellspring of calm, clear and fathomless love. Repeat 3 to 6 times before going on to the rest of your meditation practice, including the suggestion above.
Study the lives of saints, especially those who express devotion deeply and clearly. Study the lives of great men and women of courage and inspiration.
Blessings to you and may the Light of Divine Love show you the way!