First we clear our concept.
In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object.
So, if there is no tension, means if there is no force, strings or cables or chains will be loose and their purpose will not serve. I think you should be clear by now that the tension is necessary for the cables, etc. to serve their purpose. If the cables or chains are weak, what will happen, any more tension will break them. The strength of the cables or chain or wires is the main factor that we consider while we give pulling force to them between the objects.
So, what I feel that the tension is not the cause of our discomfort, rather it is the lack or deficiency of our inner strength. So, stress or what we call tension breaks the person only when he is weak. Therefore, we need to workout on our inner strength only.
Another concept we need to clear is : Stress is equal to the challenges divided by the inner strength, mathematically explained below:
STRESS = Challenges
So, we can see stress is directly proportional to challenges and inversely proportional to inner strength. As the challenges are increased, stress is increased and if the inner strength is increased, stress is decreased.
So, there is need to workout on inner strength.
Yoga definitely helps in minimising the advese effects of stress as well as minimising stress itself. But we need to take the help of holistic yoga - physical as well as inner yoga.
You can refer to our earlier answer at http://www.askyogaexpert.org/answers2questions/89/can-you-further-explain-about-relaxation-techniques
Daily Meditation to develop your inner strength as well as Chanting Om 21 times daily will help you in managing your stress or tension. Developing awareness towards your breath during meditation as well as doing pranayamas - naada-anusandhana pranayama will definitely help you. However, you also need to work on your time management, task priorities, emotional development and positive thinking to successfully challenge your challenges. All the best!