Can sternocleidomastoid muscle tightness make mastoids process more prominent than on the other side? Also have ear pressure and slight cheek numbnes

I suppose. it is theoretically possible to get a so-called "tug lesion"(bone overgrowth at the tendon insertion) at the mastoid process due to long-standing, sustained abnormal muscle traction or dysfunction, but I have never seen it or heard of it in that location. Most likely there is another reason for what you are feeling.

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Can tight sternocleidomastoid. Muscle make mastoid proces more prominent on one side. Also have ear pressure and numbness on a cheek all same side

Yes. The sternocleidomastoid (SCM) muscle inserts into the sternoclavicular area and then runs up into an insertion directly into the mastoid process Thus, if the SCM muscle is in spasm or tight, it will pull on the mastoid process likely causing inflammation and swelling. The masseter muscle in your cheek is also connected to the mastoid process, and, could tighten w/ hyperspasmodic activity in former. Read more...