Is there any particular reason why you have 1pF at the output of the second stage? Is that your load? If you're trying to compensate, you should do that at the output of the OTA stage, where you have the highest impedance. If you do it in the second stage as well, you're bringing in that pole closer to the dominant pole, which will worsen your stability. If that is a load capacitance, you might need to further decrease your output resistance so you can push that pole out further. Also, it may be possible that you might be seeing resonance as a result of interaction between two poles that are too close together. I have seen this behavior with source followers and flipped voltage followers that make use of local feedback.