Dreams and visions about a fence, wall or shielding represent the personal boundary. You can think of protecting and demarcating yourself and your environment. It reflects your aura, your spirit, your soul, your inner and outer boundaries. Dreaming about a fence, wall also indicates your source, your base, your heart - you can experience this both positively and negatively - who will let you in and who will not, and so on.
Another important explanation is that a fence or wall, shield indicates or can experience limitations, obstacles and blockages in life. The higher the fence, the shielding, the higher you experience the blockage and setback.
An additional explanation to this is that there is a barrier hindering your personal and inner growth and that you cannot move forward.
alternative dream and vision explanation is that you may have become accustomed to old habits and way of life. Staying within personal boundaries, not being able or willing to look outside the box. The self-imposed limitations, boundaries that you do not want or cannot cross, this can have a reference to a past life, a trauma, memory, stuck pattern, obstacle that keeps coming back and so on.