Local pain can continue to occur from the neurofibroma that might still press on neurological structures in spite of laminectomy, instability from the surgery itself or from degeneration of the discs or facets in the surgical region.
A new MRI is warranted. If the canal appears decompressed, then attention is brought to the discs. The laminectomy increases the “bending forward forces” (flexion) of the thoracic spine. If the disc is degenerative and a pain generator, then being upright will increase pain and lying down will decrease pain.
Occasionally, the facets can cause pain. Facet blocks (see website) can help to determine if the facets are pain generators.