Massage involves stimulation and mobilisation of superficial and deeper layers of muscle and connective tissue, to enhance function, aid in the healing process, and promote relaxation and well-being. When there is chronic soft tissue tension injury, there may be adhesions (bands of painful, rigid tissue). These adhesions can cause pain and limited movement. massage can have a therapeutic effect to help relieve pain caused by adhesions.
There are many different techniques and types of massage therapy. There are also many different therapists that provide massage as a common form of treatment for acute and chronic pain. Fortunately, your foot is a body part where one can use self-massage unlike your back. This means that you if you receive massage from a therapist, you can supplement this by applying self massage regularly at home. An easy way to do this is to use a massage ball such as the one demonstrated in the picture above. There many different types of massage equipment, which come in all different shapes and sizes and it can become a bit of a mind field when trying to choose the right product. My advice is to keep it simple and inexpensive. You're looking for a product that you can comfortably roll from your heel, along the sole of the foot towards the toes and back, repeating in a slow controlled fashion. Some people prefer a firm material whilst others a softer material. You can improvise with a tennis ball or golf ball and it really depends on what feels right for you. The aim of self-massage is to create a therapeutic affect, meaning that you should feel better after doing it. If not then you may not be doing it right.
Massage therapy in isolation is unlikely to resolve plantar fasciitis in the long term as this treatment does not address any underlying mechanical cause of the condition. It does in most cases, however, provide a therapeutic benefit to the patient and complements other mechanical treatment modalities to aid the healing the process.