It’s one thing pulling into the right lane, if one exists, to let a faster vehicle pass. However, you should never pull onto the shoulder for any reason except for mechanical or physical difficulty; it’s for emergencies, not politeness. It’s your lane, own it. If somebody wants to get past you they will. We’ve all been stuck, both in cars and on bikes, behind vehicles going too slow for our liking. We either accept where we are or pass when we’re able to, not a major thing. Concentrate on your riding and what’s ahead rather than the feelings of whoever is behind you. Be aware of them, especially if you think they’re going to pass you, but do not obsess about them. They’ll deal.
Glad to hear that you and the bike came away only slightly grazed.