If you have a muscle knot in your neck, can it cause you to be able to feel a lump or a bump?

No. a muscle spasm feel like a knot. Rest, warm shower and NSAIDs may help. Do not check frequently it will worsen the spasm. takes 1 to 2 wks for relief.
Muscle problem . it is possible to develop a nodule or firm area in your neck muscles from a tear or injury to the muscle. You need to be evaluated to make sure that there isn't something else going on like an enlarged lymph node, cyst, or other type of growth. You should see an ENT.