Connecting a capacitor on the output of an op amp can often lead to oscillations instead of the expected response. Also, the amplifier feedback resistors can interact with the amplifier input capacitance causing oscillations. These issues are called op amp loop stability. There are multiple different ways to determine if your circuit is unstable, and also multiple ways to solve stability problems. Below are links to good articles, presentations, and videos on the subject. I hope this is helpful to you!
Link 
Abstract 
This presentation introduces Op Amp Stability Basics. Multiple simulation, and calculation methods describe how to determine if a circuit is stable. Methods for correcting stability issues with Riso, and feedback capacitors are covered. Methods for determining output impedance are covered. Dual feedback path topologies are covered. Finally, 9 different ways to stabilize a circuit are covered. 

This content will focus on the concepts presented for V I Circuits driving Inductive loads. Detailed definition by example circuits contain formulae for re use. We will be focusing on the key points of these designs. Presentation is available to refer back to for detailed design help 

TI video series on the subject of stability. 

Determine Optimal Isolation Resistance for Driving Capacitive Load 
Article simplifying the selection of isolation resistance. 
Short summary on key points of stability. 