Hello Claire. It is wonderful that you decided to branch out into making homemade roti. Flatbreads can be deceptively tricky when you are first starting out, but the issues you experienced are very common and completely fixable.
Based on your description, there are three primary factors that caused your dough to become stiff and tear: the type of flour used, the hydration level, and the resting time.
First, standard supermarket whole wheat flour in Western grocery stores is milled differently than traditional Indian atta flour. Standard whole wheat flour contains coarse, sharp flakes of bran and germ that physically cut through the gluten strands as you knead and roll, leading to tearing. Traditional atta is stone-ground very finely, which allows the dough to remain smooth and elastic. If you can visit an Indian grocer or order chakki atta, it will make an immediate difference. If using regular whole wheat flour, you may want to sift out the largest bran flakes or blend it with a little all-purpose flour.
Second, whole wheat absorbs a significant amount of liquid. If the dough felt like workout equipment while kneading, it was simply under-hydrated. Roti dough should feel very soft, smooth, and supple, almost like an earlobe or play dough, rather than stiff bread dough. Do not hesitate to add warm water gradually until you reach that soft consistency.
Third, resting is essential. After kneading for about five to seven minutes, the gluten is tense and the bran needs time to fully absorb the moisture and soften. Covering the dough with a damp cloth and letting it rest for at least twenty to thirty minutes allows the gluten network to relax completely. If you skip this rest or rush it, the dough will fight your rolling pin and rip apart.
For your next batch, try using warm-to-hot water, aim for a soft and pliable dough, and give it a proper thirty-minute rest before rolling. You should see a night-and-day difference in softness and rollability.
