u/Equivalent-Maize-928

I’m 37. Doing flexibility, strength and / or dance like once/ twice a week since 10 years. This is a pose I’m proud of, but I hope getting better at this, what can I do to grow in this pose? I saw a photo pf 5 years a go and didn’t feel I get any progress. Also this aches my back. is my technique okay? Stretching is something I don’t do in class, but at home. Constructive feedback or tips are welcome. Thank you!