Yes, I have had T1 for 30 years and had frozen shoulder starting a few months ago.
The good news I have been told and have read, is that between physical therapy and slow self-healing it almost always clears itself up. And that starting PT early seems to reduce the overall duration.
The bad news is that it takes time, and it still hurt me a lot, not so much during the day, but at night when I was trying to sleep. I'd find one good position and then roll over a little bit and wake up in pain. After I woke up crying a few times (a grown man crying in bed) I decided going to see the doc was the right thing. But you're right, for me during the day, not being able to play with the kids and the dog, with anything involving sudden movements of my arm or throwing things or lifting over my head with that arm, was a downer.
It also made it hard for me to dress myself. Putting on a T-shirt was nearly impossible. Putting on a button down shirt required some careful ordering to get my arms through the holes in an order that would work. For a while I couldn't pull my wallet out of my back pocket using the bad shoulder.
The therapists are pretty good but still breaking up the scar tissue requires moving the joint into places where it is kinda between sore and painful. It's not all bad, most of the exercises they have me do just puts it into sore, but there are a couple of oddball positions the therapist loves to put me into that make me wince. After most sessions there's a soreness but it's a good kind of soreness, meaning that I have stretched my arms into positions that I haven't been able to reach for a while.
I've been doing PT for only 6 weeks now, and they also gave me a steroid injection into the joint about 8 weeks ago. The improvement has been remarkable. By no means am I back to 100%, but the PT can show me the range of motion I've regained and it is really encouraging.
They warned me (and I'd read about) steroid effects on my bg, but I noticed no change in insulin needs. I actually boosted my basal in sort of a proactive way, expecting a bg rise, but I had to back it back down to my usual basal because I was going hypo all the time.
My personal theory is that a lot of the inflammatory part of frozen shoulder has little to do with bg control and is more closely related to the auto-immune aspects of diabetes. e.g. when my thyroid got swollen because I was hypothyroid and needed to take synthroid, nobody told me it was my fault because my bg's were out of high, although there are some here who think that high bg's cause thyroid problems. Similarly my pet theory is that frozen shoulder is also mostly an autoimmune thing. My A1C's have been in the 5's or very low 6's for most of the time I've been having A1C tests run (didn't have them for the first 5 or 6 years I had diabetes, or I didn't know the results back then.)