One of the inaccurate things that some people think about Reiki energy treatments, is that it is massage. Reiki is not massage. It is not a manipulative procedure at all. The practitioner places their hands gently on the client, in either set positions, on the head, etc, or places their hands using their intuition, and where it feels that the energy is going to. There is no pressure used. Also if the client wishes, the treatment can be done without contact at all, so then the hands will be held a small distance away without contact. But usually people have Reiki energy using contact.
If you go to see someone who uses pressure during a Reiki session, ask them to stop. If they are qualified in something else, they still should not do it within a Reiki session, unless you have booked for that. Reiki has no contra -indications, and one of the reasons is that it is not a manipulative procedure. Another reason is that you are simply placing your hands gently on the customer, or holding them above without touching at all. And it is a natural healing energy which cannot harm.
It is possible to have Reiki within a massage treatment, if you have booked for a massage with Reiki. I give these treatments myself, as do other qualified therapists. I am a qualified massage therapist, aromatherapist and Reiki Master, so I understand the differences and similarities.